Digital broadcasting system and method of processing data in digital broadcasting system

ABSTRACT

A digital broadcasting system and a data processing method are disclosed. The data processing method includes receiving a broadcast signal in which main service data and mobile service data are multiplexed, demodulating the broadcast signal to acquire fast-information-channel signaling information including reference time information for a system clock, and outputting demodulation time information of a specific position of a frame of the broadcast signal, decoding the fast-information-channel signaling information, and establishing the reference time information as the system clock at a demodulation time according to on the outputted demodulation time information and decoding the mobile service data according to the system clock.

This application claims the benefit of U.S. Provisional Application No.60/957,714, filed on Aug. 24, 2007, which is hereby incorporated byreference. Also, this application claims the benefit of U.S. ProvisionalApplication No. 60/974,084, filed on Sep. 21, 2007, which is herebyincorporated by reference. This application also claims the benefit ofU.S. Provisional Application No. 60/977,379, filed on Oct. 4, 2007,which is hereby incorporated by reference. This application also claimsthe benefit of U.S. Provisional Application No. 60/971,578, filed onSep. 12, 2007, which is hereby incorporated by reference. Thisapplication also claims the benefit of U.S. Provisional Application No.61/044,504, filed on Apr. 13, 2008, which is hereby incorporated byreference. This application also claims the benefit of U.S. ProvisionalApplication No. 61/076,686, filed on Jun. 29, 2008, which is herebyincorporated by reference. This application also claims the prioritybenefit of Korean Application No. 10-2008-0083069, filed on Aug. 25,2008, which is hereby incorporated by reference

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a digital broadcasting system, and moreparticularly, to a digital broadcasting system and a data processingmethod.

2. Discussion of the Related Art

The Vestigial Sideband (VSB) transmission mode, which is adopted as thestandard for digital broadcasting in North America and the Republic ofKorea, is a system using a single carrier method. Therefore, thereceiving performance of the digital broadcast receiving system may bedeteriorated in a poor channel environment. Particularly, sinceresistance to changes in channels and noise is more highly required whenusing portable and/or mobile broadcast receivers, the receivingperformance may be even more deteriorated when transmitting mobileservice data by the VSB transmission mode.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a digital broadcastingsystem and a data processing method that are highly resistant to channelchanges and noise. An object of the present invention is to provide adigital broadcasting system and a method of processing data in a digitalbroadcasting system that can enhance the receiving performance of areceiving system (or receiver) by having a transmitting system (ortransmitter) perform additional encoding on mobile service data. Anotherobject of the present invention is to provide a digital broadcastingsystem and a method of processing data in the digital broadcastingsystem that can also enhance the receiving performance of a digitalbroadcast receiving system by inserting known data already known inaccordance with a pre-agreement between the receiving system and thetransmitting system in a predetermined region within a data region.

Another object of the present invention is to provide a digitalbroadcasting system which can process service data, beingdiscontinuously received with time, at a constant bitrate, and a dataprocessing method for use in the same.

The present invention provides a data processing method. The dataprocessing method includes receiving a broadcast signal in which mainservice data and mobile service data are multiplexed, demodulating thebroadcast signal to acquire fast-information-channel signalinginformation including reference time information for a system clock, andoutputting demodulation time information of a specific position of aframe of the broadcast signal, decoding the fast-information-channelsignaling information, and establishing the reference time informationas the system clock at a demodulation time according to on the outputteddemodulation time information and decoding the mobile service dataaccording to the system clock.

In another aspect, the present invention provides a digital broadcastingsystem. The digital broadcasting system includes a receiver configuredto receive a broadcast signal in which main service data and mobileservice data are multiplexed, a demodulator configured to demodulate thebroadcast signal to acquire fast-information-channel signalinginformation including reference time information for a system clock, andoutput demodulation time information of a specific position of a frameof the broadcast signal, a manager configured to establish the referencetime information as the system clock at a demodulation time according toon the demodulation time information using the fast-information-channelsignaling information, a decoder configured to decode the mobile servicedata according to the system clock, and a display configured to displaycontent data contained in the decoded mobile service data.

The reference time information is a Network Time Protocol (NTP)timestamp. The mobile service data is contained in data groups in thebroadcast signal, where the data groups are time-discontinuouslyreceived. Content data contained in the mobile service data is outputtedusing the system clock according to the reference time information.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings;

FIG. 1 illustrates a block diagram showing a general structure of adigital broadcasting receiving system according to an embodiment of thepresent invention;

FIG. 2 illustrates an exemplary structure of a data group according tothe present invention;

FIG. 3 illustrates an RS frame according to an embodiment of the presentinvention;

FIG. 4 illustrates an example of an MH frame structure for transmittingand receiving mobile service data according to the present invention;

FIG. 5 illustrates an example of a general VSB frame structure;

FIG. 6 illustrates a example of mapping positions of the first 4 slotsof a sub-frame in a spatial area with respect to a VSB frame;

FIG. 7 illustrates a example of mapping positions of the first 4 slotsof a sub-frame in a chronological (or time) area with respect to a VSBframe;

FIG. 8 illustrates an exemplary order of data groups being assigned toone of 5 sub-frames configuring an MH frame according to the presentinvention;

FIG. 9 illustrates an example of a single parade being assigned to an MHframe according to the present invention;

FIG. 10 illustrates an example of 3 parades being assigned to an MHframe according to the present invention;

FIG. 11 illustrates an example of the process of assigning 3 paradesshown in FIG. 10 being expanded to 5 sub-frames within an MH frame;

FIG. 12 illustrates a data transmission structure according to anembodiment of the present invention, wherein signaling data are includedin a data group so as to be transmitted;

FIG. 13 illustrates a hierarchical signaling structure according to anembodiment of the present invention;

FIG. 14 illustrates an exemplary FIC body format according to anembodiment of the present invention;

FIG. 15 illustrates an exemplary bit stream syntax structure withrespect to an FIC segment according to an embodiment of the presentinvention;

FIG. 16 illustrates an exemplary bit stream syntax structure withrespect to a payload of an FIC segment according to the presentinvention, when an FIC type field value is equal to ‘0’;

FIG. 17 illustrates an exemplary bit stream syntax structure of aservice map table according to the present invention;

FIG. 18 illustrates an exemplary bit stream syntax structure of an MHaudio descriptor according to the present invention;

FIG. 19 illustrates an exemplary bit stream syntax structure of an MHRTP payload type descriptor according to the present invention;

FIG. 20 illustrates an exemplary bit stream syntax structure of an MHcurrent event descriptor according to the present invention;

FIG. 21 illustrates an exemplary bit stream syntax structure of an MHnext event descriptor according to the present invention;

FIG. 22 illustrates an exemplary bit stream syntax structure of an MHsystem time descriptor according to the present invention;

FIG. 23 illustrates segmentation and encapsulation processes of aservice map table according to the present invention; and

FIG. 24 illustrates a flow chart for accessing a virtual channel usingFIC and SMT according to the present invention.

FIG. 25 shows an example of a timing model according to the presentinvention;

FIG. 26 shows a bitrate varying with time when a signal is transmittedand received by a time-slicing scheme according to the presentinvention;

FIG. 27 is another example of FIC segment data according to the presentinvention;

FIG. 28 is a block diagram illustrating a digital broadcasting systemaccording to another embodiment of the present invention;

FIG. 29 shows a relationship between an NTP timestamp and a PCR in a PMTaccording to the present invention;

FIG. 30 is another example of an FIC segment according to the presentinvention;

FIG. 31 is another example of an FIC segment according to the presentinvention; and

FIG. 32 is a flow chart illustrating a data processing method accordingto the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

Hereinafter, the preferred embodiment of the present invention will bedescribed with reference to the accompanying drawings. At this time, itis to be understood that the following detailed description of thepresent invention illustrated in the drawings and described withreference to the drawings are exemplary and explanatory and technicalspirits of the present invention and main features and operation of thepresent invention will not be limited by the following detaileddescription.

DEFINITION OF TERMS USED IN THE PRESENT INVENTION

Although general terms, which are widely used considering functions inthe present invention, have been selected in the present invention, theymay be changed depending on intention of those skilled in the art,practices, or new technology. Also, in specific case, the applicant mayoptionally select the terms. In this case, the meaning of the terms willbe described in detail in the description part of the invention.Therefore, it is to be understood that the terms should be defined basedupon their meaning not their simple title and the whole description ofthe present invention.

Among the terms used in the description of the present invention, mainservice data correspond to data that can be received by a fixedreceiving system and may include audio/video (A/V) data. Morespecifically, the main service data may include A/V data of highdefinition (HD) or standard definition (SD) levels and may also includediverse data types required for data broadcasting. Also, the known datacorrespond to data pre-known in accordance with a pre-arranged agreementbetween the receiving system and the transmitting system.

Additionally, among the terms used in the present invention, “MH”corresponds to the initials of “mobile” and “handheld” and representsthe opposite concept of a fixed-type system. Furthermore, the MH servicedata may include at least one of mobile service data and handheldservice data, and will also be referred to as “mobile service data” forsimplicity. Herein, the mobile service data not only correspond to MHservice data but may also include any type of service data with mobileor portable characteristics. Therefore, the mobile service dataaccording to the present invention are not limited only to the MHservice data.

The above-described mobile service data may correspond to data havinginformation, such as program execution files, stock information, and soon, and may also correspond to A/V data. Most particularly, the mobileservice data may correspond to A/V data having lower resolution andlower data rate as compared to the main service data. For example, if anA/V codec that is used for a conventional main service corresponds to aMPEG-2 codec, a MPEG-4 advanced video coding (AVC) or scalable videocoding (SVC) having better image compression efficiency may be used asthe A/V codec for the mobile service. Furthermore, any type of data maybe transmitted as the mobile service data. For example, transportprotocol expert group (TPEG) data for broadcasting real-timetransportation information may be transmitted as the main service data.

Also, a data service using the mobile service data may include weatherforecast services, traffic information services, stock informationservices, viewer participation quiz programs, real-time polls andsurveys, interactive education broadcast programs, gaming services,services providing information on synopsis, character, background music,and filming sites of soap operas or series, services providinginformation on past match scores and player profiles and achievements,and services providing information on product information and programsclassified by service, medium, time, and theme enabling purchase ordersto be processed. Herein, the present invention is not limited only tothe services mentioned above.

In the present invention, the transmitting system provides backwardcompatibility in the main service data so as to be received by theconventional receiving system. Herein, the main service data and themobile service data are multiplexed to the same physical channel andthen transmitted.

Furthermore, the digital broadcast transmitting system according to thepresent invention performs additional encoding on the mobile servicedata and inserts the data already known by the receiving system andtransmitting system (e.g., known data), thereby transmitting theprocessed data.

Therefore, when using the transmitting system according to the presentinvention, the receiving system may receive the mobile service dataduring a mobile state and may also receive the mobile service data withstability despite various distortion and noise occurring within thechannel.

Receiving System

FIG. 1 illustrates a block diagram showing a general structure of adigital broadcasting receiving system according to an embodiment of thepresent invention. The digital broadcast receiving system according tothe present invention includes a baseband processor 100, a managementprocessor 200, and a presentation processor 300.

The baseband processor 100 includes an operation controller 110, a tuner120, a demodulator 130, an equalizer 140, a known sequence detector (orknown data detector) 150, a block decoder (or mobile handheld blockdecoder) 160, a promary Reed-Solomon (RS) frame decoder 170, a secondaryRS frame decoder 180, and a signaling decoder 190. The operationcontroller 110 controls the operation of each block included in thebaseband processor 100.

By tuning the receiving system to a specific physical channel frequency,the tuner 120 enables the receiving system to receive main service data,which correspond to broadcast signals for fixed-type broadcast receivingsystems, and mobile service data, which correspond to broadcast signalsfor mobile broadcast receiving systems. At this point, the tunedfrequency of the specific physical channel is down-converted to anintermediate frequency (IF) signal, thereby being outputted to thedemodulator 130 and the known sequence detector 140. The passbanddigital IF signal being outputted from the tuner 120 may only includemain service data, or only include mobile service data, or include bothmain service data and mobile service data.

The demodulator 130 performs self-gain control, carrier wave recovery,and timing recovery processes on the passband digital IF signal inputtedfrom the tuner 120, thereby modifying the IF signal to a basebandsignal. Then, the demodulator 130 outputs the baseband signal to theequalizer 140 and the known sequence detector 150. The demodulator 130uses the known data symbol sequence inputted from the known sequencedetector 150 during the timing and/or carrier wave recovery, therebyenhancing the demodulating performance.

The equalizer 140 compensates channel-associated distortion included inthe signal demodulated by the demodulator 130. Then, the equalizer 140outputs the distortion-compensated signal to the blcok decoder 160. Byusing a known data symbol sequence inputted from the lnown sequencedetector 150, the equalizer 140 may enhance the equalizing performance.Furthermore, the equalizer 140 may receive feed-back on the decodingresult from the block decoder 160, thereby enhancing the equalizingperformance.

The known sequence detector 150 detects known data place (or position)inserted by the transmitting system from the input/output data (i.e.,data prior to being demodulated or data being processed with partialdemodulation). Then, the known sequence detector 150 outputs thedetected known data position information and known data sequencegenerated from the detected position information to the demodulator 130and the equalizer 140. Additionally, in order to allow the block decoder160 to identify the mobile service data that have been processed withadditional encoding by the transmitting system and the main service datathat have not been processed with any additional encoding, the knownsequence detector 150 outputs such corresponding information to theblock decoder 160.

If the data channel-equalized by the equalizer 140 and inputted to theblock decoder 160 correspond to data processed with both block-encodingand trellis-encoding by the transmitting system (i.e., data within theRS frame, signaling data), the block decoder 160 may performtrellis-decoding and block-decoding as inverse processes of thetransmitting system. On the other hand, if the data channel-equalized bythe equalizer 140 and inputted to the block decoder 160 correspond todata processed only with trellis-encoding and not block-encoding by thetransmitting system (i.e., main service data), the block decoder 160 mayperform only trellis-decoding.

The signaling decoder 190 decoded signaling data that have beenchannel-equalized and inputted from the equalizer 140. It is assumedthat the signaling data inputted to the signaling decoder 190 correspondto data processed with both block-encoding and trellis-encoding by thetransmitting system. Examples of such signaling data may includetransmission parameter channel (TPC) data and fast information channel(FIC) data. Each type of data will be described in more detail in alater process. The FIC data decoded by the signaling decoder 190 areoutputted to the FIC handler 215. And, the TPC data decoded by thesignaling decoder 190 are outputted to the TPC handler 214.

Meanwhile, according to the present invention, the transmitting systemuses RS frames by encoding units. Herein, the RS frame may be dividedinto a primary RS frame and a secondary RS frame. However, according tothe embodiment of the present invention, the primary RS frame and thesecondary RS frame will be divided based upon the level of importance ofthe corresponding data.

The primary RS frame decoder 170 receives the data outputted from theblock decoder 160. At this point, according to the embodiment of thepresent invention, the primary RS frame decoder 170 receives only themobile service data that have been Reed-Solomon (RS)-encoded and/orcyclic redundancy check (CRC)-encoded from the block decoder 160.Herein, the primary RS frame decoder 170 receives only the mobileservice data and not the main service data.

The primary RS frame decoder 170 performs inverse processes of an RSframe encoder (not shown) included in the digital broadcast transmittingsystem, thereby correcting errors existing within the primary RS frame.More specifically, the primary RS frame decoder 170 forms a primary RSframe by grouping a plurality of data groups and, then, correct errorsin primary RS frame units. In other words, the primary RS frame decoder170 decodes primary RS frames, which are being transmitted for actualbroadcast services.

Additionally, the secondary RS frame decoder 180 receives the dataoutputted from the block decoder 160. At this point, according to theembodiment of the present invention, the secondary RS frame decoder 180receives only the mobile service data that have been RS-encoded and/orCRC-encoded from the block decoder 160. Herein, the secondary RS framedecoder 180 receives only the mobile service data and not the mainservice data. The secondary RS frame decoder 180 performs inverseprocesses of an RS frame encoder (not shown) included in the digitalbroadcast transmitting system, thereby correcting errors existing withinthe secondary RS frame. More specifically, the secondary RS framedecoder 180 forms a secondary RS frame by grouping a plurality of datagroups and, then, correct errors in secondary RS frame units. In otherwords, the secondary RS frame decoder 180 decodes secondary RS frames,which are being transmitted for mobile audio service data, mobile videoservice data, guide data, and so on.

Meanwhile, the management processor 200 according to an embodiment ofthe present invention includes an MH physical adaptation processor 210,an IP network stack 220, a streaming handler 230, a system information(SI) handler 240, a file handler 250, a multi-purpose internet mainextensions (MIME) type handler 260, and an electronic service guide(ESG) handler 270, and an ESG decoder 280, and a storage unit 290.

The MH physical adaptation processor 210 includes a primary RS framehandler 211, a secondary RS frame handler 212, an MH transport packet(TP) handler 213, a TPC handler 214, an FIC handler 215, and a physicaladaptation control signal handler 216.

The TPC handler 214 receives and processes baseband information requiredby modules corresponding to the MH physical adaptation processor 210.The baseband information is inputted in the form of TPC data. Herein,the TPC handler 214 uses this information to process the FIC data, whichhave been sent from the baseband processor 100.

The TPC data are transmitted from the transmitting system to thereceiving system via a predetermined region of a data group. The TPCdata may include at least one of an MH ensemble ID, an MH sub-framenumber, a total number of MH groups (TNoG), an RS frame continuitycounter, a column size of RS frame (N), and an FIC version number.

Herein, the MH ensemble ID indicates an identification number of each MHensemble carried in the corresponding channel. The MH sub-frame numbersignifies a number identifying the MH sub-frame number in an MH frame,wherein each MH group associated with the corresponding MH ensemble istransmitted. The TNoG represents the total number of MH groups includingall of the MH groups belonging to all MH parades included in an MHsub-frame.

The RS frame continuity counter indicates a number that serves as acontinuity counter of the RS frames carrying the corresponding MHensemble. Herein, the value of the RS frame continuity counter shall beincremented by 1 modulo 16 for each successive RS frame.

N represents the column size of an RS frame belonging to thecorresponding MH ensemble. Herein, the value of N determines the size ofeach MH TP.

Finally, the FIC version number signifies the version number of an FICbody carried on the corresponding physical channel.

As described above, diverse TPC data are inputted to the TPC handler 214via the signaling decoder 190 shown in FIG. 1. Then, the received TPCdata are processed by the TPC handler 214. The received TPC data mayalso be used by the FIC handler 215 in order to process the FIC data.

The FIC handler 215 processes the FIC data by associating the FIC datareceived from the baseband processor 100 with the TPC data.

The physical adaptation control signal handler 216 collects FIC datareceived through the FIC handler 215 and SI data received through RSframes. Then, the physical adaptation control signal handler 216 usesthe collected FIC data and SI data to configure and process IP datagramsand access information of mobile broadcast services. Thereafter, thephysical adaptation control signal handler 216 stores the processed IPdatagrams and access information to the storage unit 290.

The primary RS frame handler 211 identifies primary RS frames receivedfrom the primary RS frame decoder 170 of the baseband processor 100 foreach row unit, so as to configure an MH TP. Thereafter, the primary RSframe handler 211 outputs the configured MH TP to the MH TP handler 213.

The secondary RS frame handler 212 identifies secondary RS framesreceived from the secondary RS frame decoder 180 of the basebandprocessor 100 for each row unit, so as to configure an MH TP.Thereafter, the secondary RS frame handler 212 outputs the configured MHTP to the MH TP handler 213.

The MH transport packet (TP) handler 213 extracts a header from each MHTP received from the primary RS frame handler 211 and the secondary RSframe handler 212, thereby determining the data included in thecorresponding MH TP. Then, when the determined data correspond to SIdata (i.e., SI data that are not encapsulated to IP datagrams), thecorresponding data are outputted to the physical adaptation controlsignal handler 216. Alternatively, when the determined data correspondto an IP datagram, the corresponding data are outputted to the IPnetwork stack 220.

The IP network stack 220 processes broadcast data that are beingtransmitted in the form of IP datagrams. More specifically, the IPnetwork stack 220 processes data that are inputted via user datagramprotocol (UDP), real-time transport protocol (RTP), real-time transportcontrol protocol (RTCP), asynchronous layered coding/layered codingtransport (ALC/LCT), file delivery over unidirectional transport(FLUTE), and so on. Herein, when the processed data correspond tostreaming data, the corresponding data are outputted to the streaminghandler 230. And, when the processed data correspond to data in a fileformat, the corresponding data are outputted to the file handler 250.Finally, when the processed data correspond to SI-associated data, thecorresponding data are outputted to the SI handler 240.

The SI handler 240 receives and processes SI data having the form of IPdatagrams, which are inputted to the IP network stack 220. When theinputted data associated with SI correspond to MIME-type data, theinputted data are outputted to the MIME-type handler 260. The MIME-typehandler 260 receives the MIME-type SI data outputted from the SI handler240 and processes the received MIME-type SI data.

The file handler 250 receives data from the IP network stack 220 in anobject format in accordance with the ALC/LCT and FLUTE structures. Thefile handler 250 groups the received data to create a file format.Herein, when the corresponding file includes ESG, the file is outputtedto the ESG handler 270. On the other hand, when the corresponding fileincludes data for other file-based services, the file is outputted tothe presentation controller 330 of the presentation processor 300.

The ESG handler 270 processes the ESG data received from the filehandler 250 and stores the processed ESG data to the storage unit 290.Alternatively, the ESG handler 270 may output the processed ESG data tothe ESG decoder 280, thereby allowing the ESG data to be used by the ESGdecoder 280.

The storage unit 290 stores the system information (SI) received fromthe physical adaptation control signal handler 210 and the ESG handler270 therein. Thereafter, the storage unit 290 transmits the stored SIdata to each block.

The ESG decoder 280 either recovers the ESG data and SI data stored inthe storage unit 290 or recovers the ESG data transmitted from the ESGhandler 270. Then, the ESG decoder 280 outputs the recovered data to thepresentation controller 330 in a format that can be outputted to theuser.

The streaming handler 230 receives data from the IP network stack 220,wherein the format of the received data are in accordance with RTPand/or RTCP structures. The streaming handler 230 extracts audio/videostreams from the received data, which are then outputted to theaudio/video (A/V) decoder 310 of the presentation processor 300. Theaudio/video decoder 310 then decodes each of the audio stream and videostream received from the streaming handler 230.

The display module 320 of the presentation processor 300 receives audioand video signals respectively decoded by the A/V decoder 310. Then, thedisplay module 320 provides the received audio and video signals to theuser through a speaker and/or a screen.

The presentation controller 330 corresponds to a controller managingmodules that output data received by the receiving system to the user.

The channel service manager 340 manages an interface with the user,which enables the user to use channel-based broadcast services, such aschannel map management, channel service connection, and so on.

The application manager 350 manages an interface with a user using ESGdisplay or other application services that do not correspond tochannel-based services.

Meanwhile, The streaming handler 230 may include a buffer temporarilystoring audio/video data. The digital broadcasting reception systemperiodically sets reference time information to a system time clock, andthen the stored audio/video data can be transferred to A/V decoder 310at a constant bitrate. Accordingly, the audio/video data can beprocessed at a bitrate and audio/video service can be provided.

Data Format Structure

Meanwhile, the data structure used in the mobile broadcasting technologyaccording to the embodiment of the present invention may include a datagroup structure and an RS frame structure, which will now be describedin detail.

FIG. 2 illustrates an exemplary structure of a data group according tothe present invention.

FIG. 2 shows an example of dividing a data group according to the datastructure of the present invention into 10 MH blo In this example, eachMH block has the length of 16 segments. Referring to FIG. 2, only the RSparity data are allocated to portions of the first 5 segments of the MHblock 1 (B1) and the last 5 segments of the MH block 10 (B10). The RSparity data are excluded in regions A to D of the data group.

More specifically, when it is assumed that one data group is dividedinto regions A, B, C, and D, each MH block may be included in any one ofregion A to region D depending upon the characteristic of each MH blockwithin the data group.

Herein, the data group is divided into a plurality of regions to be usedfor different purposes. More specifically, a region of the main servicedata having no interference or a very low interference level may beconsidered to have a more resistant (or stronger) receiving performanceas compared to regions having higher interference levels. Additionally,when using a system inserting and transmitting known data in the datagroup, wherein the known data are known based upon an agreement betweenthe transmitting system and the receiving system, and when consecutivelylong known data are to be periodically inserted in the mobile servicedata, the known data having a predetermined length may be periodicallyinserted in the region having no interference from the main service data(i.e., a region wherein the main service data are not mixed). However,due to interference from the main service data, it is difficult toperiodically insert known data and also to insert consecutively longknown data to a region having interference from the main service data.

Referring to FIG. 2, MH block 4 (B4) to MH block 7 (B7) correspond toregions without interference of the main service data. MH block 4 (B4)to MH block 7 (B7) within the data group shown in FIG. 2 correspond to aregion where no interference from the main service data occurs. In thisexample, a long known data sequence is inserted at both the beginningand end of each MH block. In the description of the present invention,the region including MH block 4 (B4) to MH block 7 (B7) will be referredto as “region A (=B4+B5+B6+B7)”. As described above, when the data groupincludes region A having a long known data sequence inserted at both thebeginning and end of each MH block, the receiving system is capable ofperforming equalization by using the channel information that can beobtained from the known data. Therefore, the strongest equalizingperformance may be yielded (or obtained) from one of region A to regionD.

In the example of the data group shown in FIG. 2, MH block 3 (B3) and MHblock 8 (B8) correspond to a region having little interference from themain service data. Herein, a long known data sequence is inserted inonly one side of each MH block B3 and B8. More specifically, due to theinterference from the main service data, a long known data sequence isinserted at the end of MH block 3 (B3), and another long known datasequence is inserted at the beginning of MH block 8 (B8). In the presentinvention, the region including MH block 3 (B3) and MH block 8 (B8) willbe referred to as “region B (=B3+B8)”. As described above, when the datagroup includes region B having a long known data sequence inserted atonly one side (beginning or end) of each MH block, the receiving systemis capable of performing equalization by using the channel informationthat can be obtained from the known data. Therefore, a strongerequalizing performance as compared to region C/D may be yielded (orobtained).

Referring to FIG. 2, MH block 2 (B2) and MH block 9 (B9) correspond to aregion having more interference from the main service data as comparedto region B. A long known data sequence cannot be inserted in any sideof MH block 2 (B2) and MH block 9 (B9). Herein, the region including MHblock 2 (B2) and MH block 9 (B9) will be referred to as “region C(=B2+B9)”.

Finally, in the example shown in FIG. 2, MH block 1 (B1) and MH block 10(B10) correspond to a region having more interference from the mainservice data as compared to region C. Similarly, a long known datasequence cannot be inserted in any side of MH block 1 (B1) and MH block10 (B10). Herein, the region including MH block 1 (B1) and MH block 10(B10) will be referred to as “region D (=B1+B10)”. Since region C/D isspaced further apart from the known data sequence, when the channelenvironment undergoes frequent and abrupt changes, the receivingperformance of region C/D may be deteriorated.

Additionally, the data group includes a signaling information areawherein signaling information is assigned (or allocated).

In the present invention, the signaling information area may start fromthe 1^(st) segment of the 4^(th) MH block (B4) to a portion of the2^(nd) segment.

According to an embodiment of the present invention, the signalinginformation area for inserting signaling information may start from the1^(st) segment of the 4^(th) MH block (B4) to a portion of the 2^(nd)segment. More specifically, 276(=207+69) bytes of the 4^(th) MH block(B4) in each data group are assigned as the signaling information area.In other words, the signaling information area consists of 207 bytes ofthe 1^(st) segment and the first 69 bytes of the 2^(nd) segment of the4^(th) MH block (B4). The 1^(st) segment of the 4^(th) MH block (B4)corresponds to the 17^(th) or 173^(rd) segment of a VSB field.

Herein, the signaling information may be identified by two differenttypes of signaling channels: a transmission parameter channel (TPC) anda fast information channel (FIC).

Herein, the TPC data may include at least one of an MH ensemble ID, anMH sub-frame number, a total number of MH groups (TNoG), an RS framecontinuity counter, a column size of RS frame (N), and an FIC versionnumber. However, the TPC data (or information) presented herein aremerely exemplary. And, since the adding or deleting of signalinginformation included in the TPC data may be easily adjusted and modifiedby one skilled in the art, the present invention will, therefore, not belimited to the examples set forth herein. Furthermore, the FIC isprovided to enable a fast service acquisition of data receivers, and theFIC includes cross layer information between the physical layer and theupper layer(s). For example, when the data group includes 6 known datasequences, as shown in FIG. 2, the signaling information area is locatedbetween the first known data sequence and the second known datasequence. More specifically, the first known data sequence is insertedin the last 2 segments of the 3^(rd) MH block (B3), and the second knowndata sequence in inserted in the 2^(nd) and 3^(rd) segments of the4^(th) MH block (B4). Furthermore, the 3^(rd) to 6^(th) known datasequences are respectively inserted in the last 2 segments of each ofthe 4^(th), 5^(th), 6^(th), and 7^(th) MH blocks (B4, B5, B6, and B7).The 1^(st) and 3^(rd) to 6^(th) known data sequences are spaced apart by16 segments.

FIG. 3 illustrates an RS frame according to an embodiment of the presentinvention.

The RS frame shown in FIG. 3 corresponds to a collection of one or moredata groups. The RS frame is received for each MH frame in a conditionwhere the receiving system receives the FIC and processes the receivedFIC and where the receiving system is switched to a time-slicing mode sothat the receiving system can receive MH ensembles including ESG entrypoints. Each RS frame includes IP streams of each service or ESG, andSMT section data may exist in all RS frames.

The RS frame according to the embodiment of the present inventionconsists of at least one MH transport packet (TP). Herein, the MH TPincludes an MH header and an MH payload.

The MH payload may include mobile service data as weak as signalingdata. More specifically, an MH payload may include only mobile servicedata, or may include only signaling data, or may include both mobileservice data and signaling data.

According to the embodiment of the present invention, the MH header mayidentify (or distinguish) the data types included in the MH payload.More specifically, when the MH TP includes a first MH header, thisindicates that the MH payload includes only the signaling data. Also,when the MH TP includes a second MH header, this indicates that the MHpayload includes both the signaling data and the mobile service data.Finally, when MH TP includes a third MH header, this indicates that theMH payload includes only the mobile service data.

In the example shown in FIG. 3, the RS frame is assigned with IPdatagrams (IP datagram 1 and IP datagram 2) for two service types.

The IP datagram in the MH-TP in the RS frame may include reference timeinformation (for example, network time stamp (NTP)), the detaileddescription for the reference time information will be disclosed bybeing referred to FIGS. 25 to 29.

Data Transmission Structure

FIG. 4 illustrates a structure of a MH frame for transmitting andreceiving mobile service data according to the present invention.

In the example shown in FIG. 4, one MH frame consists of 5 sub-frames,wherein each sub-frame includes 16 slots. In this case, the MH frameaccording to the present invention includes 5 sub-frames and 80 slots.

Also, in a packet level, one slot is configured of 156 data packets(i.e., transport stream packets), and in a symbol level, one slot isconfigured of 156 data segments. Herein, the size of one slotcorresponds to one half (½) of a VSB field. More specifically, since one207-byte data packet has the same amount of data as a data segment, adata packet prior to being interleaved may also be used as a datasegment. At this point, two VSB fields are grouped to form a VSB frame.

FIG. 5 illustrates an exemplary structure of a VSB frame, wherein oneVSB frame consists of 2 VSB fields (i.e., an odd field and an evenfield). Herein, each VSB field includes a field synchronization segmentand 312 data segments. The slot corresponds to a basic time unit formultiplexing the mobile service data and the main service data. Herein,one slot may either include the mobile service data or be configuredonly of the main service data.

If the first 118 data packets within the slot correspond to a datagroup, the remaining 38 data packets become the main service datapackets. In another example, when no data group exists in a slot, thecorresponding slot is configured of 156 main service data packets.

Meanwhile, when the slots are assigned to a VSB frame, an off-set existsfor each assigned position.

FIG. 6 illustrates a mapping example of the positions to which the first4 slots of a sub-frame are assigned with respect to a VSB frame in aspatial area. And, FIG. 7 illustrates a mapping example of the positionsto which the first 4 slots of a sub-frame are assigned with respect to aVSB frame in a chronological (or time) area.

Referring to FIG. 6 and FIG. 7, a 38^(th) data packet (TS packet #37) ofa 1^(st) slot (Slot #0) is mapped to the 1^(st) data packet of an oddVSB field. A 38^(th) data packet (TS packet #37) of a 2^(nd) slot (Slot#1) is mapped to the 157^(th) data packet of an odd VSB field. Also, a38^(th) data packet (TS packet #37) of a 3^(rd) slot (Slot #2) is mappedto the 1^(st) data packet of an even VSB field. And, a 38^(th) datapacket (TS packet #37) of a 4^(th) slot (Slot #3) is mapped to the157^(th) data packet of an even VSB field. Similarly, the remaining 12slots within the corresponding sub-frame are mapped in the subsequentVSB frames using the same method.

FIG. 8 illustrates an exemplary assignment order of data groups beingassigned to one of 5 sub-frames, wherein the 5 sub-frames configure anMH frame. For example, the method of assigning data groups may beidentically applied to all MH frames or differently applied to each MHframe. Furthermore, the method of assigning data groups may beidentically applied to all sub-frames or differently applied to eachsub-frame. At this point, when it is assumed that the data groups areassigned using the same method in all sub-frames of the corresponding MHframe, the total number of data groups being assigned to an MH frame isequal to a multiple of ‘5’.

According to the embodiment of the present invention, a plurality ofconsecutive data groups is assigned to be spaced as far apart from oneanother as possible within the MH frame. Thus, the system can be capableof responding promptly and effectively to any burst error that may occurwithin a sub-frame.

For example, when it is assumed that 3 data groups are assigned to asub-frame, the data groups are assigned to a 1^(st) slot (Slot #0), a5^(th) slot (Slot #4), and a 9^(th) slot (Slot #8) in the sub-frame,respectively. FIG. 8 illustrates an example of assigning 16 data groupsin one sub-frame using the above-described pattern (or rule). In otherwords, each data group is serially assigned to 16 slots corresponding tothe following numbers: 0, 8, 4, 12, 1, 9, 5, 13, 2, 10, 6, 14, 3, 11, 7,and 15. Equation 1 below shows the above-described rule (or pattern) forassigning data groups in a sub-frame.

j=(4i+0)mod 16  [Equation 1]

-   -   0=0 if i<4,    -   0=2 else if i<8,

Herein,

-   -   0=1 else if i<12,    -   0=3 else.

Herein, j indicates the slot number within a sub-frame. The value of jmay range from 0 to 15 (i.e., 0≦j≦15). Also, variable i indicates thedata group number. The value of i may range from 0 to 15 (i.e., 0≦i≦15).

In the present invention, a collection of data groups included in a MHframe will be referred to as a “parade”. Based upon the RS frame mode,the parade transmits data of at least one specific RS frame.

The mobile service data within one RS frame may be assigned either toall of regions A/B/C/D within the corresponding data group, or to atleast one of regions A/B/C/D. In the embodiment of the presentinvention, the mobile service data within one RS frame may be assignedeither to all of regions A/B/C/D, or to at least one of regions A/B andregions C/D. If the mobile service data are assigned to the latter case(i.e., one of regions A/B and regions C/D), the RS frame being assignedto regions A/B and the RS frame being assigned to regions C/D within thecorresponding data group are different from one another.

According to the embodiment of the present invention, the RS frame beingassigned to regions A/B within the corresponding data group will bereferred to as a “primary RS frame”, and the RS frame being assigned toregions C/D within the corresponding data group will be referred to as a“secondary RS frame”, for simplicity. Also, the primary RS frame and thesecondary RS frame form (or configure) one parade. More specifically,when the mobile service data within one RS frame are assigned either toall of regions A/B/C/D within the corresponding data group, one paradetransmits one RS frame. Conversely, when the mobile service data withinone RS frame are assigned either to at least one of regions A/B andregions C/D, one parade may transmit up to 2 RS frames. Morespecifically, the RS frame mode indicates whether a parade transmits oneRS frame, or whether the parade transmits two RS frames. Such RS framemode is transmitted as the above-described TPC data. Table 1 below showsan example of the RS frame mode.

TABLE 1 RS frame mode (2 bits) Description 00 There is only one primaryRS frame for all group regions 01 There are two separate RS frames.Primary RS frame for group regions A and B Secondary RS frame for groupregions C and D 10 Reserved 11 Reserved

Table 1 illustrates an example of allocating 2 bits in order to indicatethe RS frame mode. For example, referring to Table 1, when the RS framemode value is equal to ‘00’, this indicates that one parade transmitsone RS frame. And, when the RS frame mode value is equal to ‘01’, thisindicates that one parade transmits two RS frames, i.e., the primary RSframe and the secondary RS frame.

More specifically, when the RS frame mode value is equal to ‘01’, dataof the primary RS frame for regions A/B are assigned and transmitted toregions A/B of the corresponding data group. Similarly, data of thesecondary RS frame for regions C/D are assigned and transmitted toregions C/D of the corresponding data group.

As described in the assignment of data groups, the parades are alsoassigned to be spaced as far apart from one another as possible withinthe sub-frame. Thus, the system can be capable of responding promptlyand effectively to any burst error that may occur within a sub-frame.Furthermore, the method of assigning parades may be identically appliedto all MH frames or differently applied to each MH frame.

According to the embodiment of the present invention, the parades may beassigned differently for each MH frame and identically for allsub-frames within an MH frame. More specifically, the MH frame structuremay vary by MH frame units. Thus, an ensemble rate may be adjusted on amore frequent and flexible basis.

FIG. 9 illustrates an example of multiple data groups of a single paradebeing assigned (or allocated) to an MH frame. More specifically, FIG. 9illustrates an example of a plurality of data groups included in asingle parade, wherein the number of data groups included in a sub-frameis equal to ‘3’, being allocated to an MH frame.

Referring to FIG. 9, 3 data groups are sequentially assigned to asub-frame at a cycle period of 4 slots. Accordingly, when this processis equally performed in the 5 sub-frames included in the correspondingMH frame, 15 data groups are assigned to a single MH frame. Herein, the15 data groups correspond to data groups included in a parade.Therefore, since one sub-frame is configured of 4 VSB frame, and since 3data groups are included in a sub-frame, the data group of thecorresponding parade is not assigned to one of the 4 VSB frames within asub-frame.

For example, when it is assumed that one parade transmits one RS frame,and that a RS frame encoder (not shown) included in the transmittingsystem performs RS-encoding on the corresponding RS frame, therebyadding 24 bytes of parity data to the corresponding RS frame andtransmitting the processed RS frame, the parity data occupyapproximately 11.37% (=24/(187+24)×100) of the total code word length.Meanwhile, when one sub-frame includes 3 data groups, and when the datagroups included in the parade are assigned, as shown in FIG. 9, a totalof 15 data groups form an RS frame. Accordingly, even when an erroroccurs in an entire data group due to a burst noise within a channel,the percentile is merely 6.67% (=1/15×100). Therefore, the receivingsystem may correct all errors by performing an erasure RS decodingprocess. More specifically, when the erasure RS decoding is performed, anumber of channel errors corresponding to the number of RS parity bytesmay be corrected. By doing so, the receiving system may correct theerror of at least one data group within one parade. Thus, the minimumburst noise length correctable by a RS frame is over 1 VSB frame.

Meanwhile, when data groups of a parade are assigned as shown in FIG. 9,either main service data may be assigned between each data group, ordata groups corresponding to different parades may be assigned betweeneach data group. More specifically, data groups corresponding tomultiple parades may be assigned to one MH frame.

Basically, the method of assigning data groups corresponding to multipleparades is very similar to the method of assigning data groupscorresponding to a single parade. In other words, data groups includedin other parades that are to be assigned to an MH frame are alsorespectively assigned according to a cycle period of 4 slots.

At this point, data groups of a different parade may be sequentiallyassigned to the respective slots in a circular method. Herein, the datagroups are assigned to slots starting from the ones to which data groupsof the previous parade have not yet been assigned.

For example, when it is assumed that data groups corresponding to aparade are assigned as shown in FIG. 9, data groups corresponding to thenext parade may be assigned to a sub-frame starting either from the12^(th) slot of a sub-frame. However, this is merely exemplary. Inanother example, the data groups of the next parade may also besequentially assigned to a different slot within a sub-frame at a cycleperiod of 4 slots starting from the 3^(rd) slot.

FIG. 10 illustrates an example of transmitting 3 parades (Parade #0,Parade #1, and Parade #2) to an MH frame. More specifically, FIG. 10illustrates an example of transmitting parades included in one of 5sub-frames, wherein the 5 sub-frames configure one MH frame.

When the 1^(st) parade (Parade #0) includes 3 data groups for eachsub-frame, the positions of each data groups within the sub-frames maybe obtained by substituting values ‘0’ to ‘2’ for i in Equation 1. Morespecifically, the data groups of the 1^(st) parade (Parade #0) aresequentially assigned to the 1^(st), 5^(th), and 9^(th) slots (Slot #0,Slot #4, and Slot #8) within the sub-frame.

Also, when the 2^(nd) parade includes 2 data groups for each sub-frame,the positions of each data groups within the sub-frames may be obtainedby substituting values ‘3’ and ‘4’ for i in Equation 1. Morespecifically, the data groups of the 2^(nd) parade (Parade #1) aresequentially assigned to the 2^(nd) and 12^(th) slots (Slot #3 and Slot#11) within the sub-frame.

Finally, when the 3^(rd) parade includes 2 data groups for eachsub-frame, the positions of each data groups within the sub-frames maybe obtained by substituting values ‘5’ and ‘6’ for i in Equation 1. Morespecifically, the data groups of the 3^(rd) parade (Parade #2) aresequentially assigned to the 7^(th) and 11^(th) slots (Slot #6 and Slot#10) within the sub-frame.

As described above, data groups of multiple parades may be assigned to asingle MH frame, and, in each sub-frame, the data groups are seriallyallocated to a group space having 4 slots from left to right.

Therefore, a number of groups of one parade per sub-frame (NoG) maycorrespond to any one integer from ‘1’ to ‘8’. Herein, since one MHframe includes 5 sub-frames, the total number of data groups within aparade that can be allocated to an MH frame may correspond to any onemultiple of ‘5’ ranging from ‘5’ to ‘40’.

FIG. 11 illustrates an example of expanding the assignment process of 3parades, shown in FIG. 10, to 5 sub-frames within an MH frame.

FIG. 12 illustrates a data transmission structure according to anembodiment of the present invention, wherein signaling data are includedin a data group so as to be transmitted.

As described above, an MH frame is divided into 5 sub-frames. Datagroups corresponding to a plurality of parades co-exist in eachsub-frame. Herein, the data groups corresponding to each parade aregrouped by MH frame units, thereby configuring a single parade. The datastructure shown in FIG. 12 includes 3 parades, one ESG dedicated channel(EDC) parade (i.e., parade with NoG=1), and 2 service parades (i.e.,parade with NoG=4 and parade with NoG=3). Also, a predetermined portionof each data group (i.e., 37 bytes/data group) is used for delivering(or sending) FIC information associated with mobile service data,wherein the FIC information is separately encoded from the RS-encodingprocess. The FIC region assigned to each data group consists of one FICsegments. Herein, each segment is interleaved by MH sub-frame units,thereby configuring an FIC body, which corresponds to a completed FICtransmission structure. However, whenever required, each segment may beinterleaved by MH frame units and not by MH sub-frame units, therebybeing completed in MH frame units.

Meanwhile, the concept of an MH ensemble is applied in the embodiment ofthe present invention, thereby defining a collection (or group) ofservices. Each MH ensemble carries the same QoS and is coded with thesame FEC code. Also, each MH ensemble has the same unique identifier(i.e., ensemble ID) and corresponds to consecutive RS frames.

As shown in FIG. 12, the FIC segment corresponding to each data groupdescribed service information of an MH ensemble to which thecorresponding data group belongs. When FIC segments within a sub-frameare grouped and deinterleaved, all service information of a physicalchannel through which the corresponding FICs are transmitted may beobtained. Therefore, the receiving system may be able to acquire thechannel information of the corresponding physical channel, after beingprocessed with physical channel tuning, during a sub-frame period.

Furthermore, FIG. 12 illustrates a structure further including aseparate EDC parade apart from the service parade and wherein electronicservice guide (ESG) data are transmitted in the 1^(st) slot of eachsub-frame.

If the digital broadcasting reception system recognizes a frame startpoint or a frame end point of the MH frame (or the MH subframe), thenthe digital broadcasting reception system can set the reference timeinformation to the system time clock at the frame start point or theframe end point. The reference time information can be the network timeprotocol (NTP) timestamp. The detailed description for the referencetime information will be disclosed by being referred to FIGS. 25 to 29.

Hierarchical Signaling Structure

FIG. 13 illustrates a hierarchical signaling structure according to anembodiment of the present invention. As shown in FIG. 13, the mobilebroadcasting technology according to the embodiment of the presentinvention adopts a signaling method using FIC and SMT. In thedescription of the present invention, the signaling structure will bereferred to as a hierarchical signaling structure.

Hereinafter, a detailed description on how the receiving system accessesa virtual channel via FIC and SMT will now be given with reference toFIG. 13.

The FIC body defined in an MH transport (M1) identifies the physicallocation of each the data stream for each virtual channel and providesvery high level descriptions of each virtual channel.

Being MH ensemble level signaling information, the service map table(SMT) provides MH ensemble level signaling information. The SMT providesthe IP access information of each virtual channel belonging to therespective MH ensemble within which the SMT is carried. The SMT alsoprovides all IP stream component level information required for thevirtual channel service acquisition.

Referring to FIG. 13, each MH ensemble (i.e., Ensemble 0, Ensemble 1, .. . , Ensemble K) includes a stream information on each associated (orcorresponding) virtual channel (e.g., virtual channel 0 IP stream,virtual channel 1 IP stream, and virtual channel 2 IP stream). Forexample, Ensemble 0 includes virtual channel 0 IP stream and virtualchannel 1 IP stream. And, each MH ensemble includes diverse informationon the associated virtual channel (i.e., Virtual Channel 0 Table Entry,Virtual Channel 0 Access Info, Virtual Channel 1 Table Entry, VirtualChannel 1 Access Info, Virtual Channel 2 Table Entry, Virtual Channel 2Access Info, Virtual Channel N Table Entry, Virtual Channel N AccessInfo, and so on).

The FIC body payload includes information on MH ensembles (e.g.,ensemble_id field, and referred to as “ensemble location” in FIG. 13)and information on a virtual channel associated with the correspondingMH ensemble (e.g., when such information corresponds to amajor_channel_num field and a minor_channel_num field, the informationis expressed as Virtual Channel 0, Virtual Channel 1, Virtual Channel Nin FIG. 13).

The application of the signaling structure in the receiving system willnow be described in detail.

When a user selects a channel he or she wishes to view (hereinafter, theuser-selected channel will be referred to as “channel θ” forsimplicity), the receiving system first parses the received FIC. Then,the receiving system acquires information on an MH ensemble (i.e.,ensemble location), which is associated with the virtual channelcorresponding to channel θ (hereinafter, the corresponding MH ensemblewill be referred to as “MH ensemble θ” for simplicity). By acquiringslots only corresponding to the MH ensemble θ using the time-slicingmethod, the receiving system configures ensemble θ. The ensemble θconfigured as described above, includes an SMT on the associated virtualchannels (including channel θ) and IP streams on the correspondingvirtual channels. Therefore, the receiving system uses the SMT includedin the MH ensemble θ in order to acquire various information on channelθ (e.g., Virtual Channel θ Table Entry) and stream access information onchannel θ (e.g., Virtual Channel θ Access Info). The receiving systemuses the stream access information on channel θ to receive only theassociated IP streams, thereby providing channel θ services to the user.

Fast Information Channel (FIC)

The digital broadcast receiving system according to the presentinvention adopts the fast information channel (FIC) for a faster accessto a service that is currently being broadcasted.

More specifically, the FIC handler 215 of FIG. 1 parses the FIC body,which corresponds to an FIC transmission structure, and outputs theparsed result to the physical adaptation control signal handler 216.

FIG. 14 illustrates an exemplary FIC body format according to anembodiment of the present invention. According to the embodiment of thepresent invention, the FIC format consists of an FIC body header and anFIC body payload.

Meanwhile, according to the embodiment of the present invention, dataare transmitted through the FIC body header and the FIC body payload inFIC segment units. Each FIC segment has the size of 37 bytes, and eachFIC segment consists of a 2-byte FIC segment header and a 35-byte FICsegment payload. More specifically, an FIC body configured of an FICbody header and an FIC body payload, is segmented in units of 35 databytes, which are then carried in at least one FIC segment within the FICsegment payload, so as to be transmitted.

In the description of the present invention, an example of inserting oneFIC segment in one data group, which is then transmitted, will be given.In this case, the receiving system receives a slot corresponding to eachdata group by using a time-slicing method.

The signaling decoder 190 included in the receiving system shown in FIG.1 collects each FIC segment inserted in each data group. Then, thesignaling decoder 190 uses the collected FIC segments to created asingle FIC body. Thereafter, the signaling decoder 190 performs adecoding process on the FIC body payload of the created FIC body, sothat the decoded FIC body payload corresponds to an encoded result of asignaling encoder (not shown) included in the transmitting system.Subsequently, the decoded FIC body payload is outputted to the FIChandler 215. The FIC handler 215 parses the FIC data included in the FICbody payload, and then outputs the parsed FIC data to the physicaladaptation control signal handler 216. The physical adaptation controlsignal handler 216 uses the inputted FIC data to perform processesassociated with MH ensembles, virtual channels, SMTs, and so on.

According to an embodiment of the present invention, when an FIC body issegmented, and when the size of the last segmented portion is smallerthan 35 data bytes, it is assumed that the lacking number of data bytesin the FIC segment payload is completed with by adding the same numberof stuffing bytes therein, so that the size of the last FIC segment canbe equal to 35 data bytes.

However, it is apparent that the above-described data byte values (i.e.,37 bytes for the FIC segment, 2 bytes for the FIC segment header, and 35bytes for the FIC segment payload) are merely exemplary, and will,therefore, not limit the scope of the present invention.

FIG. 15 illustrates an exemplary bit stream syntax structure withrespect to an FIC segment according to an embodiment of the presentinvention.

Herein, the FIC segment signifies a unit used for transmitting the FICdata. The FIC segment consists of an FIC segment header and an FICsegment payload. Referring to FIG. 15, the FIC segment payloadcorresponds to the portion starting from the ‘for’ loop statement.Meanwhile, the FIC segment header may include a FIC_type field, anerror_indicator field, an FIC_seg_number field, and anFIC_last_seg_number field. A detailed description of each field will nowbe given.

The FIC_type field is a 2-bit field indicating the type of thecorresponding FIC.

The error_indicator field is a 1-bit field, which indicates whether ornot an error has occurred within the FIC segment during datatransmission. If an error has occurred, the value of the error_indicatorfield is set to ‘1’. More specifically, when an error that has failed tobe recovered still remains during the configuration process of the FICsegment, the error_indicator field value is set to ‘1’. Theerror_indicator field enables the receiving system to recognize thepresence of an error within the FIC data.

The FIC_seg_number field is a 4-bit field. Herein, when a single FICbody is divided into a plurality of FIC segments and transmitted, theFIC_seg_number field indicates the number of the corresponding FICsegment.

Finally, the FIC_last_seg_number field is also a 4-bit field. TheFIC_last_seg_number field indicates the number of the last FIC segmentwithin the corresponding FIC body.

FIG. 16 illustrates an exemplary bit stream syntax structure withrespect to a payload of an FIC segment according to the presentinvention, when an FIC type field value is equal to ‘0’.

According to the embodiment of the present invention, the payload of theFIC segment is divided into 3 different regions. A first region of theFIC segment payload exists only when the FIC_seg_number field value isequal to ‘0’. Herein, the first region may include acurrent_next_indicator field, an ESG_version field, and atransport_stream id field. However, depending upon the embodiment of thepresent invention, it may be assumed that each of the 3 fields existsregardless of the FIC_seg_number field.

The current_next_indicator field is a 1-bit field. The current_nextindicator field acts as an indicator identifying whether thecorresponding FIC data carry MH ensemble configuration information of anMH frame including the current FIC segment, or whether the correspondingFIC data carry MH ensemble configuration information of a next MH frame.

The ESG_version field is a 5-bit field indicating ESG versioninformation. Herein, by providing version information on the serviceguide providing channel of the corresponding ESG, the ESG_version fieldenables the receiving system to notify whether or not the correspondingESG has been updated.

Finally, the transport_stream id field is a 16-bit field acting as aunique identifier of a broadcast stream through which the correspondingFIC segment is being transmitted.

A second region of the FIC segment payload corresponds to an ensembleloop region, which includes an ensemble_id field, an SI_version field,and a num channel field.

More specifically, the ensemble_id field is an 8-bit field indicatingidentifiers of an MH ensemble through which MH services are transmitted.The MH services will be described in more detail in a later process.Herein, the ensemble_id field binds the MH services and the MH ensemble.

The SI_version field is a 4-bit field indicating version information ofSI data included in the corresponding ensemble, which is beingtransmitted within the RS frame.

Finally, the num_channel field is an 8-bit field indicating the numberof virtual channel being transmitted via the corresponding ensemble.

A third region of the FIC segment payload a channel loop region, whichincludes a channel_type field, a channel_activity field, a CA_indicatorfield, a stand_alone_service_indicator field, a major_channel_num field,and a minor_channel_num field.

The channel_type field is a 5-bit field indicating a service type of thecorresponding virtual channel. For example, the channel_type field mayindicates an audio/video channel, an audio/video and data channel, anaudio-only channel, a data-only channel, a file download channel, an ESGdelivery channel, a notification channel, and so on.

The channel_activity field is a 2-bit field indicating activityinformation of the corresponding virtual channel. More specifically, thechannel_activity field may indicate whether the current virtual channelis providing the current service.

The CA_indicator field is a 1-bit field indicating whether or not aconditional access (CA) is applied to the current virtual channel.

The stand_alone_service_indicator field is also a 1-bit field, whichindicates whether the service of the corresponding virtual channelcorresponds to a stand alone service.

The major_channel_num field is an 8-bit field indicating a major channelnumber of the corresponding virtual channel.

Finally, the minor_channel_num field is also an 8-bit field indicating aminor channel number of the corresponding virtual channel.

Service Table Map

FIG. 17 illustrates an exemplary bit stream syntax structure of aservice map table (hereinafter referred to as “SMT”) according to thepresent invention.

According to the embodiment of the present invention, the SMT isconfigured in an MPEG-2 private section format. However, this will notlimit the scope and spirit of the present invention. The SMT accordingto the embodiment of the present invention includes descriptioninformation for each virtual channel within a single MH ensemble. And,additional information may further be included in each descriptor area.

Herein, the SMT according to the embodiment of the present inventionincludes at least one field and is transmitted from the transmittingsystem to the receiving system.

As described in FIG. 3, the SMT section may be transmitted by beingincluded in the MH TP within the RS frame. In this case, each of the RSframe decoders 170 and 180, shown in FIG. 1, decodes the inputted RSframe, respectively. Then, each of the decoded RS frames is outputted tothe respective RS frame handler 211 and 212. Thereafter, each RS framehandler 211 and 212 identifies the inputted RS frame by row units, so asto create an MH TP, thereby outputting the created MH TP to the MH TPhandler 213. When it is determined that the corresponding MH TP includesan SMT section based upon the header in each of the inputted MH TP, theMH TP handler 213 parses the corresponding SMT section, so as to outputthe SI data within the parsed SMT section to the physical adaptationcontrol signal handler 216. However, this is limited to when the SMT isnot encapsulated to IP datagrams.

Meanwhile, when the SMT is not encapsulated to IP datagrams, and when itis determined that the corresponding MH TP includes an SMT section basedupon the header in each of the inputted MH TP, the MH TP handler 213outputs the SMT section to the IP network stack 220. Accordingly, the IPnetwork stack 220 performs IP and UDP processes on the inputted SMTsection and, then, outputs the processed SMT section to the SI handler240. The SI handler 240 parses the inputted SMT section and controls thesystem so that the parsed SI data can be stored in the storage unit 290.

The following corresponds to example of the fields that may betransmitted through the SMT.

The table_id field corresponds to an 8-bit unsigned integer number,which indicates the type of table section.

The table_id field allows the corresponding table to be defined as theservice map table (SMT).

The ensemble_id field is an 8-bit unsigned integer field, whichcorresponds to an ID value associated to the corresponding MH ensemble.Herein, the ensemble_id field may be assigned with a value ranging fromrange ‘0x00’ to ‘0x3F’. It is preferable that the value of theensemble_id field is derived from the parade_id of the TPC data, whichis carried from the baseband processor of MH physical layer subsystem.When the corresponding MH ensemble is transmitted through (or carriedover) the primary RS frame, a value of ‘0’ may be used for the mostsignificant bit (MSB), and the remaining 7 bits are used as theparade_id value of the associated MH parade (i.e., for the leastsignificant 7 bits). Alternatively, when the corresponding MH ensembleis transmitted through (or carried over) the secondary RS frame, a valueof ‘1’ may be used for the most significant bit (MSB).

The num_channels field is an 8-bit field, which specifies the number ofvirtual channels in the corresponding SMT section.

Meanwhile, the SMT according to the embodiment of the present inventionprovides information on a plurality of virtual channels using the ‘for’loop statement.

The major_channel_num field corresponds to an 8-bit field, whichrepresents the major channel number associated with the correspondingvirtual channel. Herein, the major_channel_num field may be assignedwith a value ranging from ‘0x00’ to ‘0xFF’.

The minor_channel_num field corresponds to an 8-bit field, whichrepresents the minor channel number associated with the correspondingvirtual channel. Herein, the minor_channel_num field may be assignedwith a value ranging from ‘0x00’ to ‘0xFF’.

The short_channel_name field indicates the short name of the virtualchannel.

The service_id field is a 16-bit unsigned integer number (or value),which identifies the virtual channel service.

The service_type field is a 6-bit enumerated type field, whichdesignates the type of service carried in the corresponding virtualchannel as defined in Table 2 below.

TABLE 2 0x00 [Reserved] 0x01 MH_digital_television field: the virtualchannel carries television programming (audio, video and optionalassociated data) conforming to ATSC standards. 0x02 MH_audio field: thevirtual channel carries audio programming (audio service and optionalassociated data) conforming to ATSC standards. 0x03 MH_data_only_servicefield: the virtual channel carries a data service conforming to ATSCstandards, but no video or audio component. 0x04 to [Reserved for futureATSC usage] 0xFF

The virtual_channel_activity field is a 2-bit enumerated fieldidentifying the activity status of the corresponding virtual channel.When the most significant bit (MSB) of the virtual_channel_activityfield is ‘1’, the virtual channel is active, and when the mostsignificant bit (MSB) of the virtual_channel_activity field is ‘0’, thevirtual channel is inactive. Also, when the least significant bit (LSB)of the virtual_channel_activity field is ‘1’, the virtual channel ishidden (when set to 1), and when the least significant bit (LSB) of thevirtual_channel_activity field is ‘0’, the virtual channel is nothidden.

The num_components field is a 5-bit field, which specifies the number ofIP stream components in the corresponding virtual channel.

The IP_version_flag field corresponds to a 1-bit indicator. Morespecifically, when the value of the IP_version_flag field is set to ‘1’,this indicates that a source_IP_address field, avirtual_channel_target_IP_address field, and acomponent_target_IP_address field are IPv6 addresses. Alternatively,when the value of the IP_version_flag field is set to ‘0’, thisindicates that the source_IP_address field, thevirtual_channel_target_IP_address field, and thecomponent_target_IP_address field are IPv4.

The source_IP_address_flag field is a 1-bit Boolean flag, whichindicates, when set, that a source IP address of the correspondingvirtual channel exist for a specific multicast source.

The virtual_channel_target_IP_address_flag field is a 1-bit Booleanflag, which indicates, when set, that the corresponding IP streamcomponent is delivered through IP datagrams with target IP addressesdifferent from the virtual_channel_target_IP_address. Therefore, whenthe flag is set, the receiving system (or receiver) uses thecomponent_target_IP_address as the target_IP_address in order to accessthe corresponding IP stream component. Accordingly, the receiving system(or receiver) may ignore the virtual_channel_target_IP_address fieldincluded in the num_channels loop.

The source_IP_address field corresponds to a 32-bit or 128-bit field.Herein, the source_IP_address field will be significant (or present),when the value of the source_IP_address_flag field is set to ‘1’.However, when the value of the source_IP_address_flag field is set to‘0’, the source_IP_address field will become insignificant (or absent).More specifically, when the source_IP_address_flag field value is set to‘1’, and when the IP_version_flag field value is set to ‘0’, thesource_IP_address field indicates a 32-bit IPv4 address, which shows thesource of the corresponding virtual channel. Alternatively, when theIP_version_flag field value is set to ‘1’, the source_IP_address fieldindicates a 128-bit IPv6 address, which shows the source of thecorresponding virtual channel.

The virtual_channel_target_IP_address field also corresponds to a 32-bitor 128-bit field. Herein, the virtual_channel_target_IP_address fieldwill be significant (or present), when the value of thevirtual_channel_target_IP_address_flag field is set to ‘1’. However,when the value of the virtual_channel_target_IP_address_flag field isset to ‘0’, the virtual_channel_target_IP_address field will becomeinsignificant (or absent). More specifically, when thevirtual_channel_target_IP_address_flag field value is set to ‘1’, andwhen the IP_version_flag field value is set to ‘0’, thevirtual_channel_target_IP_address field indicates a 32-bit target IPv4address associated to the corresponding virtual channel. Alternatively,when the virtual_channel_target_IP_address_flag field value is set to‘1’, and when the IP_version_flag field value is set to ‘1’, thevirtual_channel target_IP address field indicates a 64-bit target IPv6address associated to the corresponding virtual channel. If thevirtual_channel_target_IP_address field is insignificant (or absent),the component_target_IP_address field within the num_channels loopshould become significant (or present). And, in order to enable thereceiving system to access the IP stream component, thecomponent_target_IP_address field should be used.

Meanwhile, the SMT according to the embodiment of the present inventionuses a ‘for’ loop statement in order to provide information on aplurality of components.

Herein, the RTP_payload_type field, which is assigned with 7 bits,identifies the encoding format of the component based upon Table 3 shownbelow. When the IP stream component is not encapsulated to RTP, theRTP_payload_type field shall be ignored (or deprecated).

Table 3 below shows an example of an RTP payload type.

TABLE 3 RTP_payload_type Meaning 35 AVC video 36 MH audio 37 to 72[Reserved for future ATSC use]

The component_target_IP_address_flag field is a 1-bit Boolean flag,which indicates, when set, that the corresponding IP stream component isdelivered through IP datagrams with target IP addresses different fromthe virtual_channel_target_IP_address. Furthermore, when thecomponent_target_IP_address_flag is set, the receiving system (orreceiver) uses the component_target_IP_address field as the target IPaddress for accessing the corresponding IP stream component.Accordingly, the receiving system (or receiver) will ignore thevirtual_channel_target_IP_address field included in the num_channelsloop.

The component_target_IP_address field corresponds to a 32-bit or 128-bitfield. Herein, when the value of the IP_version_flag field is set to‘0’, the component_target_IP_address field indicates a 32-bit targetIPv4 address associated to the corresponding IP stream component. And,when the value of the IP_version_flag field is set to ‘1’, thecomponent_target_IP_address field indicates a 128-bit target IPv6address associated to the corresponding IP stream component.

The port_num_count field is a 6-bit field, which indicates the number ofUDP ports associated with the corresponding IP stream component. Atarget UDP port number value starts from the target_UDP_port_num fieldvalue and increases (or is incremented) by 1. For the RTP stream, thetarget UDP port number should start from the target_UDP_port_num fieldvalue and shall increase (or be incremented) by 2. This is toincorporate RTCP streams associated with the RTP streams.

The target_UDP_port_num field is a 16-bit unsigned integer field, whichrepresents the target UDP port number for the corresponding IP streamcomponent. When used for RTP streams, the value of thetarget_UDP_port_num field shall correspond to an even number. And, thenext higher value shall represent the target UDP port number of theassociated RTCP stream.

The component_level_descriptor( ) represents zero or more descriptorsproviding additional information on the corresponding IP streamcomponent.

The virtual_channel_level_descriptor( ) represents zero or moredescriptors providing additional information for the correspondingvirtual channel.

The ensemble_level_descriptor( ) represents zero or more descriptorsproviding additional information for the MH ensemble, which is describedby the corresponding SMT.

FIG. 18 illustrates an exemplary bit stream syntax structure of an MHaudio descriptor according to the present invention. When at least oneaudio service is present as a component of the current event, theMH_audio_descriptor( ) shall be used as a component_level_descriptor ofthe SMT. The MH_audio_descriptor( ) may be capable of informing thesystem of the audio language type and stereo mode status. If there is noaudio service associated with the current event, then it is preferablethat the MH_audio_descriptor( ) is considered to be insignificant (orabsent) for the current event. Each field shown in the bit stream syntaxof FIG. 18 will now be described in detail.

The descriptor_tag field is an 8-bit unsigned integer having a TBDvalue, which indicates that the corresponding descriptor is theMH_audio_descriptor( ) . The descriptor_length field is also an 8-bitunsigned integer, which indicates the length (in bytes) of the portionimmediately following the descriptor_length field up to the end of theMH_audio_descriptor( ) . The channel_configuration field corresponds toan 8-bit field indicating the number and configuration of audiochannels. The values ranging from ‘1’ to ‘6’ respectively indicate thenumber and configuration of audio channels as given for “Default bitstream index number” in Table 42 of ISO/IEC 13818-7:2006. All othervalues indicate that the number and configuration of audio channels areundefined.

The sample_rate_code field is a 3-bit field, which indicates the samplerate of the encoded audio data. Herein, the indication may correspond toone specific sample rate, or may correspond to a set of values thatinclude the sample rate of the encoded audio data as defined in TableA3.3 of ATSC A/52B. The bit_rate_code field corresponds to a 6-bitfield. Herein, among the 6 bits, the lower 5 bits indicate a nominal bitrate. More specifically, when the most significant bit (MSB) is ‘0’, thecorresponding bit rate is exact. On the other hand, when the mostsignificant bit (MSB) is ‘0’, the bit rate corresponds to an upper limitas defined in Table A3.4 of ATSC A/53B. The ISO_(—)639_language_codefield is a 24-bit (i.e., 3-byte) field indicating the language used forthe audio stream component, in conformance with ISO 639.2/B [x]. When aspecific language is not present in the corresponding audio streamcomponent, the value of each byte will be set to ‘0x00’.

FIG. 19 illustrates an exemplary bit stream syntax structure of an MHRTP payload type descriptor according to the present invention.

The MH_RTP_payload_type_descriptor( ) specifies the RTP payload type.Yet, the MH_RTP_payload_type_descriptor( ) exists only when the dynamicvalue of the RTP_payload_type field within the num_components loop ofthe SMT is in the range of ‘96’ to ‘127’. TheMH_RTP_payload_type_descriptor( ) is used as acomponent_level_descriptor of the SMT.

The MH_RTP_payload_type_descriptor translates (or matches) a dynamicRTP_payload_type field value into (or with) a MIME type. Accordingly,the receiving system (or receiver) may collect (or gather) the encodingformat of the IP stream component, which is encapsulated in RTP.

The fields included in the MH_RTP_payload_type_descriptor( ) will now bedescribed in detail.

The descriptor_tag field corresponds to an 8-bit unsigned integer havingthe value TBD, which identifies the current descriptor as theMH_RTP_payload_type_descriptor( ).

The descriptor_length field also corresponds to an 8-bit unsignedinteger, which indicates the length (in bytes) of the portionimmediately following the descriptor_length field up to the end of theMH_RTP_payload_type_descriptor( ).

The RTP_payload_type field corresponds to a 7-bit field, whichidentifies the encoding format of the IP stream component. Herein, thedynamic value of the RTP_payload_type field is in the range of ‘96’ to‘127’.

The MIME_type_length field specifies the length (in bytes) of theMIME_type field.

The MIME_type field indicates the MIME type corresponding to theencoding format of the IP stream component, which is described by theMH_RTP_payload_type_descriptor( ).

FIG. 20 illustrates an exemplary bit stream syntax structure of an MHcurrent event descriptor according to the present invention.

The MH_current_event_descriptor( ) shall be used as thevirtual_channel_level_descriptor( ) within the SMT. Herein, theMH_current_event_descriptor( ) provides basic information on the currentevent (e.g., the start time, duration, and title of the current event,etc.), which is transmitted via the respective virtual channel.

The fields included in the MH_current_event_descriptor( ) will now bedescribed in detail.

The descriptor_tag field corresponds to an 8-bit unsigned integer havingthe value TBD, which identifies the current descriptor as theMH_current_event_descriptor( ).

The descriptor_length field also corresponds to an 8-bit unsignedinteger, which indicates the length (in bytes) of the portionimmediately following the descriptor_length field up to the end of theMH_current_event_descriptor( ).

The current_event_start_time field corresponds to a 32-bit unsignedinteger quantity. The current_event_start_time field represents thestart time of the current event and, more specifically, as the number ofGPS seconds since 00:00:00 UTC, Jan. 6, 1980.

The current_event_duration field corresponds to a 24-bit field. Herein,the current_event_duration field indicates the duration of the currentevent in hours, minutes, and seconds (wherein the format is in 6 digits,4-bit BCD=24 bits).

The title_length field specifies the length (in bytes) of the title_textfield. Herein, the value ‘0’ indicates that there are no titles existingfor the corresponding event.

The title_text field indicates the title of the corresponding event inevent title in the format of a multiple string structure as defined inATSC A/65C [x].

FIG. 21 illustrates an exemplary bit stream syntax structure of an MHnext event descriptor according to the present invention.

The optional MH_next_event_descriptor( ) shall be used as thevirtual_channel_level_descriptor( ) within the SMT. Herein, theMH_next_event_descriptor( ) provides basic information on the next event(e.g., the start time, duration, and title of the next event, etc.),which is transmitted via the respective virtual channel. The fieldsincluded in the

MH_next_event_descriptor( ) will now be described in detail.

The descriptor_tag field corresponds to an 8-bit unsigned integer havingthe value TBD, which identifies the current descriptor as theMH_next_event_descriptor( ).

The descriptor_length field also corresponds to an 8-bit unsignedinteger, which indicates the length (in bytes) of the portionimmediately following the descriptor_length field up to the end of theMH_next_event_descriptor( ).

The next_event_start_time field corresponds to a 32-bit unsigned integerquantity. The next_event_start_time field represents the start time ofthe next event and, more specifically, as the number of GPS secondssince 00:00:00 UTC, Jan. 6, 1980.

The next_event_duration field corresponds to a 24-bit field. Herein, thenext_event_duration field indicates the duration of the next event inhours, minutes, and seconds (wherein the format is in 6 digits, 4-bitBCD=24 bits).

The title_length field specifies the length (in bytes) of the title_textfield. Herein, the value ‘0’ indicates that there are no titles existingfor the corresponding event.

The title_text field indicates the title of the corresponding event inevent title in the format of a multiple string structure as defined inATSC A/65C [x].

FIG. 22 illustrates an exemplary bit stream syntax structure of an MHsystem time descriptor according to the present invention.

The MH_system_time_descriptor( ) shall be used as theensemble_level_descriptor( ) within the SMT. Herein, theMH_system_time_descriptor( ) provides information on current time anddate.

The MH_system_time_descriptor( ) also provides information on the timezone in which the transmitting system (or transmitter) transmitting thecorresponding broadcast stream is located, while taking intoconsideration the mobile/portable characterstics of the MH service data.The fields included in the MH_system_time_descriptor( ) will now bedescribed in detail.

The descriptor_tag field corresponds to an 8-bit unsigned integer havingthe value TBD, which identifies the current descriptor as theMH_system_time_descriptor( ).

The descriptor_length field also corresponds to an 8-bit unsignedinteger, which indicates the length (in bytes) of the portionimmediately following the descriptor_length field up to the end of theMH_system_time_descriptor( ).

The system time field corresponds to a 32-bit unsigned integer quantity.The system_time field represents the current system time and, morespecifically, as the number of GPS seconds since 00:00:00 UTC, Jan. 6,1980.

The GPS_UTC_offset field corresponds to an 8-bit unsigned integer, whichdefines the current offset in whole seconds between GPS and UTC timestandards. In order to convert GPS time to UTC time, the GPS_UTC_offsetis subtracted from GPS time. Whenever the International Bureau ofWeights and Measures decides that the current offset is too far inerror, an additional leap second may be added (or subtracted).Accordingly, the GPS_UTC_offset field value will reflect the change.

The time_zone_offset_polarity field is a 1-bit field, which indicateswhether the time of the time zone, in which the broadcast station islocated, exceeds (or leads or is faster) or falls behind (or lags or isslower) than the UTC time. When the value of thetime_zone_offset_polarity field is equal to ‘0’, this indicates that thetime on the current time zone exceeds the UTC time. Therefore, thetime_zone_offset_polarity field value is added to the UTC time value.Conversely, when the value of the time_zone_offset_polarity field isequal to ‘1’, this indicates that the time on the current time zonefalls behind the UTC time. Therefore, the time_zone_offset_polarityfield value is subtracted from the UTC time value.

The time_zone_offset field is a 31-bit unsigned integer quantity. Morespecifically, the time_zone_offset field represents, in GPS seconds, thetime offset of the time zone in which the broadcast station is located,when compared to the UTC time.

The daylight_savings field corresponds to a 16-bit field providinginformation on the Summer Time (i.e., the Daylight Savings Time). Thetime_zone field corresponds to a (5×8)-bit field indicating the timezone, in which the transmitting system (or transmitter) transmitting thecorresponding broadcast stream is located.

FIG. 23 illustrates segmentation and encapsulation processes of aservice map table (SMT) according to the present invention.

According to the present invention, the SMT is encapsulated to UDP,while including a target IP address and a target UDP port number withinthe IP datagram.

More specifically, the SMT is first segmented into a predeterminednumber of sections, then encapsulated to a UDP header, and finallyencapsulated to an IP header. In addition, the SMT section providessignaling information on all virtual channel included in the MH ensembleincluding the corresponding SMT section. At least one SMT sectiondescribing the MH ensemble is included in each RS frame included in thecorresponding MH ensemble. Finally, each SMT section is identified by anensemble_id included in each section. According to the embodiment of thepresent invention, by informing the receiving system of the target IPaddress and target UDP port number, the corresponding data (i.e., targetIP address and target UDP port number) may be parsed without having thereceiving system to request for other additional information.

FIG. 24 illustrates a flow chart for accessing a virtual channel usingFIC and SMT according to the present invention.

More specifically, a physical channel is tuned (S501). And, when it isdetermined that an MH signal exists in the tuned physical channel(S502), the corresponding MH signal is demodulated (S503). Additionally,FIC segments are grouped from the demodulated MH signal in sub-frameunits (S504 and S505).

According to the embodiment of the present invention, an FIC segment isinserted in a data group, so as to be transmitted. More specifically,the FIC segment corresponding to each data group described serviceinformation on the MH ensemble to which the corresponding data groupbelongs. When the FIC segments are grouped in sub-frame units and, then,deinterleaved, all service information on the physical channel throughwhich the corresponding FIC segment is transmitted may be acquired.Therefore, after the tuning process, the receiving system may acquirechannel information on the corresponding physical channel during asub-frame period. Once the FIC segments are grouped, in S504 and S505, abroadcast stream through which the corresponding FIC segment is beingtransmitted is identified (S506). For example, the broadcast stream maybe identified by parsing the transport_stream_id field of the FIC body,which is configured by grouping the FIC segments.

Furthermore, an ensemble identifier, a major channel number, a minorchannel number, channel type information, and so on, are extracted fromthe FIC body (S507). And, by using the extracted ensemble information,only the slots corresponding to the designated ensemble are acquired byusing the time-slicing method, so as to configure an ensemble (S508).

Subsequently, the RS frame corresponding to the designated ensemble isdecoded (S509), and an IP socket is opened for SMT reception (S510).

According to the example given in the embodiment of the presentinvention, the SMT is encapsulated to UDP, while including a target IPaddress and a target UDP port number within the IP datagram. Morespecifically, the SMT is first segmented into a predetermined number ofsections, then encapsulated to a UDP header, and finally encapsulated toan IP header. According to the embodiment of the present invention, byinforming the receiving system of the target IP address and target UDPport number, the receiving system parses the SMT sections and thedescriptors of each SMT section without requesting for other additionalinformation (S511).

The SMT section provides signaling information on all virtual channelincluded in the MH ensemble including the corresponding SMT section. Atleast one SMT section describing the MH ensemble is included in each RSframe included in the corresponding MH ensemble. Also, each SMT sectionis identified by an ensemble_id included in each section.

Furthermore each SMT provides IP access information on each virtualchannel subordinate to the corresponding MH ensemble including each SMT.Finally, the SMT provides IP stream component level information requiredfor the servicing of the corresponding virtual channel.

Therefore, by using the information parsed from the SMT, the IP streamcomponent belonging to the virtual channel requested for reception maybe accessed (S513). Accordingly, the service associated with thecorresponding virtual channel is provided to the user (S514).

Relationship Between FIC Data and Other Data

As shown in the above-mentioned description, mobile service data andmain service data are multiplexed in the MH broadcasting signal and themultiplexed data in the MH broadcasting signal is transmitted. In orderto transmit mobile service data, transmission-parameter-channelsignaling information is established in TPC data, andfast-information-channel signaling information is established in FICdata. TPC data and FIC data are multiplexed and randomized, ¼ ParallelConcatenated Convolutional Code (PCCC) is error-correction-encoded, suchthat the PCCC-encoded data is transmitted to a data group. Otherwise,mobile service data contained in the ensemble is SCCC (SerialConcatenated Convolutional Code)-outer-encoded, such that theSCCC-encoded data is transmitted to a data group. Mobile service dataincludes content data constructing a service and service tableinformation describing this service. This service table informationincludes channel information of the ensemble indicating at least onevirtual channel group, and includes service description informationbased on channel information.

For the convenience of description, if several data segments passthrough different modulation processes in a transmission unit ordifferent demodulation processes in a reception unit although the datasegments located in the same signal frame (or the same data group), itis represented that the data segments are transferred to different datachannels because these data segments are signaling-processed viadifferent paths. For example, it can be represented that the TPC dataand FIC data are transmitted to a data channel other than a data channelin which the content data and the service table information aretransmitted. Because error correction coding/decoding processes to whichthe TPC data and FIC are applied are different from those applied to thecontent data and the service table information contained in theensemble.

Under the above-mentioned assumption, a method for receiving the MHbroadcasting signal will hereinafter be described. A digitalbroadcasting system according to the present invention receives abroadcasting signal in which mobile service data and main service dataare multiplexed. The system acquires version information of FIC datafrom TPC data received in a first data channel among mobile service dataand acquires binding information of an ensemble and a virtual channelcontained in the ensemble from the FIC data. Therefore, it can berecognized which one of ensembles transmits a service of a user-selectedvirtual channel.

Thus, the system can receive the ensemble transferring the correspondingvirtual channel according to a parade format. The system can acquiredata groups contained in a series of slots from the parade received in areceiver. If the data groups are collected during only one MH frame, thesystem can acquire the RS frame equipped with this ensemble. Therefore,the system decodes the RS frame, and parses the service tableinformation contained in the decoded RS frame. The system can acquire aservice of the virtual channel from the parsed service table informationusing information describing the user-selected virtual channel.

The FIC data transferred to a first data channel may indicate bindinginformation an ensemble and the virtual channel associated with theensemble, in which the ensemble is transferred to a second data channel.Using the binding information, the system can parse the service tableinformation contained in a specific ensemble, such that the service canbe quickly displayed.

Examples of FIC data and information contained in the FIC data are asfollows. In more detail, if the above-mentioned service is providedusing FIC data, a digital broadcasting system capable of establishingsynchronization of components constructing the service, and a dataprocessing method for use in the digital broadcasting system willhereinafter be described in detail.

FIG. 25 shows an example of a timing model according to the presentinvention. Provided that a video component and an audio component aretransmitted, an example of the reception system synchronizing the videocomponent and the audio component is as follows.

Each of the video component and the audio component is encoded, suchthat the encoded video and audio components can be stored in a buffer ofeither a data processing system or a transmission system.

The data processing system or the transmission systemencodes/multiplexes the audio and video components stored in the buffer,such that it may store or transmit the multiplexed signal.

A playback system or a reception system decodes and demultiplexesvideo/audio multiplexed signals stored in the buffer. Each of thedemultiplexed video/audio components is stored in the buffer of theplayback system or the reception system, and is decoded by each decoderof the playback system or the reception system, such that the decodedvideo/audio components can be outputted from each decoder of theplayback system or the reception system.

Each of the video and audio components to be synchronized in theabove-mentioned signal flow undergoes a time delay. For example, it isassumed that this timing model has a constant time delay which can bestored in or transferred to the storage unit (constant delay 1).

A temporary storing time, during which data is temporarily stored in thebuffer of the data processing system or the transmission system, or thebuffer of the playback system or the reception system, can be changedaccording to systems, such that the video/audio components aretime-delayed in different ways (Variable Delay).

However, in order to synchronize the video/audio components and outputthe synchronized video/audio components, it is assumed that a timedelay, which is required when the video component and the audiocomponent are transmitted to the timing model and are then outputtedfrom the timing model, is constant (Constant Delay 2).

If the above-mentioned timing model is not operated, the video/audiocomponents are not synchronized with each other, such that a user whoreceives and views content data equipped with the video/audio componentsmay feel uncomfortable. In order to overcome the above-mentionedproblem, an MPEG-2 TS system defines a system time clock as a value of27 MHz, such that the video/audio components can be synchronized witheach other.

According to contents defined by the MPEG-2 TS system, the transmissionsystem performs a PCR (Program Clock Reference) coding on a system clockfrequency, and transmits the coded result to the reception system. ThisPCR value is used to set a transmission-system time to the value of 27MHz within the range of program_clock_reference_base_field informationof the MPEG-2 TS.

The reception system sets a reception time of the last bit of theprogram_clock_reference_base_field to a system time clock (STC). If anSTC value corrected by the PCR is a decoding time stamp (DTS) containedin a packetized elementary stream (PES) and a presentation time stamp(PTS), the reception system decodes a corresponding elementary stream,and displays the decoded result on the outside.

For the convenience of description, a system clock error range of 27 MHzfor use in the MPEG-2 TS system is set to +/−810 MHz, and it is assumedthat transmission of a value of concatenated PCRs is completed within0.1 second or less.

Input signals of the MPEG-2 system decoder in the digital broadcastingreception system are output signals of the tuner or the channel decoder.In order to maintain a constant bitrate of the broadcast stream for abroadcasting signal processing, all the constituent components of thedigital broadcasting reception system are operated. If mobile servicedata is discontinuously received in the digital broadcasting receptionsystem on a time axis in the same manner as in the MH broadcastingsignal, the digital broadcasting reception system can reduce an amountof power consumption using a time-slicing method,

FIG. 26 shows a bitrate varying with time when a signal is transmittedand received by a time-slicing scheme according to the presentinvention. For example, if a first service (event) (Service 1) and asecond service (event) (Service 2) are received in a parade of the MHbroadcasting signal (i.e., if the services are received in the order ofparade indexes 1, 2, and 3), an amount of transmitted broadcast signalsis not constant in time. It is assumed that a data amount, which isequal to that of a specific case in which the digital broadcastingreception system receives mobile service data by the time slicingmethod, is received at an average bitrate in the same manner as in thespecific case. A bandwidth of mobile service data received by thetime-slicing method is larger than another bandwidth by N times, inwhich the another bandwidth is obtained when data is received at theaverage bitrate. It is assumed that a data mount of one method is equalto that of the other method.

Therefore, although the data amount obtained when the digitalbroadcasting reception system receives a broadcast signal using thetime-slicing method is equal to another data amount obtained when thedigital broadcasting reception system continues to receive a broadcastsignal. And an amount of power consumption can be reduced by 1/N+aaccording to the time-slicing method.

However, if the digital broadcasting reception system receives abroadcast signal, it is unable to receive the broadcast signal at aconstant bitrate, such that the digital broadcasting reception systemmay have difficulty in managing its buffer when the broadcast signal iscontinuously received and decoded. For example, if a time referencevalue is encoded at timing points t1 and t2 (denoted by X), and theencoded resultant data is transmitted by the MPEG-2 TS scheme, a valueof a time reference field may be different from that of an actual systemtime reference. For example, a time reference value encoded at the timet2 may correspond to a time reference value of the time t3 on thecondition that a broadcast signal is received at the actual averagebitrate. If the time reference value is transmitted and receivedaccording to the above-mentioned scheme, an additional buffer should becontained in the digital broadcasting reception system, a broadcastsignal received in the parade is stored in this additional buffer, andthen the resultant broadcast signal may be outputted at the averagebitrate.

However, the above-mentioned scheme is complicated, and the process forrecovering an original time reference by the average bitrate can becontinuously accumulated, such that this process is considered to be arecursive process, which may allow the digital broadcasting receptionsystem to be unstable more and more.

Although a time reference value is recovered by the above-mentionedscheme, the recovered time reference value may be changed according to atime at which the decoder of the digital broadcasting reception systemdecodes the broadcast signal. So, although the same digital broadcastingreception system is also used, the recovered time reference value may bechanged to another. For example, which time the digital broadcastingreception system is powered on or a channel is changed to anotherchannel, may cause a time difference in a playback of content data.

In order to easily explain the above-mentioned problem, the followingdescription will hereinafter be described with reference to FIG. 12. Ifthe digital broadcasting reception system receives one MH frame in theparade, it is able to acquire an RS frame including one or twoensembles. As previously stated above, the ensemble includes at leastone virtual channel group transferring mobile service data. For theconvenience of description and better understanding of the presentinvention, it is assumed that the digital broadcasting reception systemcan receive one ensemble from one MH frame. Thus, the digitalbroadcasting reception system requires a predetermined time of 968 msec(about 1 second) to receive one ensemble, such that it is unable torecover a system time using a scheme defined by the MPEG-2 TS.

In the case of transmitting and receiving the service using the Internetprotocol as shown in FIG. 3, constituent elements of the servicecomposed of audio- and video-data are transmitted and received asReal-time Transport Protocol (RTP) packets. An RTP packet header has atimestamp value acting as a time unit capable of processing an accessunit (AU) such as a video frame.

As a reference time of this timestamp, a timestamp of a Network TimeProtocol (NTP) and a timestamp value of a system reference clockcorresponding to this timestamp can be simultaneously transmitted to asender report (SR) packet of an RTP control protocol (RTCP).

The digital broadcasting reception system can establish synchronizationon audio/video (A/V) data received in this system reference clock.However, a reception time of an absolute time transferred to theInternet protocol may be differently assigned to individual digitalbroadcasting reception systems, such that each digital broadcastingreception system can reproduce audio/video (A/V) content data byreferring to the same time. However, display contents of the digitalbroadcasting reception systems may be unsynchronized with each other.

Therefore, the digital broadcasting reception systems can establishsynchronization of constituent components of the service (event), andcan display content data provided to this service (event) without anytime difference in the displayed content data.

The digital broadcasting reception systems receive the MH broadcastingsignal, and can transmit a reference time value at a specific time ofthe MH signal frame, such that it obtains a mobile service transferredto the received broadcast signal. For the convenience of description andbetter understanding of the present invention, the time reference valueat which the MH signal frame is transferred is hereinafter referred toas a reference time.

For example, if the digital broadcast reception system receives the MHbroadcasting signal, a specific time for the MH signal processing (e.g.,the beginning time of the MH signal frame or the beginning time of anyone of MH signal sub frames) may be used as a time for establishing thereference time. In this example, the MH frame start time of the MHsignal frame may be used as the reference time setup time. If the starttime of the MH signal frame is used as the reference time setup time,the digital broadcast reception system receiving the MH broadcastingsignals may establish the reference time at the same time as the abovereference time setup time when the Doppler effect is ignored. Also, theactual reference time value transmitted to the MH signal frame may beset to a system time clock at the same time as the above reference timesetup time.

In the above-mentioned embodiment, the reference time can be transferredto FIC data contained in the MH signal frame.

If FIC body data transferred to the MH subframe is divided into aplurality of segments, each of the segments is referred to as an FICsegment. A format of this FIC segment will hereinafter be described withreference to FIG. 15. A header of the FIC segment may include an FICtype. The format of the FIC segment data may be different according to avalue of the FIC type.

For reference, FIC data may be contained in each data group and theresultant data group including the FIC data can be transferred to adestination. Provided that the size of FIC data contained in each groupis an SOF and the number of data groups contained in the ensemble is anNoG (Number of Group), a bitrate of data which is transferred to one MHframe by the ensemble is denoted by the following equation:

NoG×SOF×5(the number of MH subframes)/0.986 byte per second.  [Equation]

FIG. 27 is another example of FIC segment data according to the presentinvention.

The FIC segment includes an FIC segment header field and an FIC segmentpayload field. The size of each field may be differently determined.

The FIC segment header may include an FIC_type field of 2 bits. If theFIC_type field is set to ‘11’, the FIC segment header may include areserved field of 6 bits after the FIC_type field. For example, if theFIC_type field is set to ‘11’, this means that the FIC segment payloadcurrently transmits a reference time.

The FIC segment payload includes an extension field of 3 bits, a lengthfield of 5 bits, and an extension payload field. For example, if theextension field of 3 bits is set to ‘000’, the extension payload fieldcan transmit the reference time. For example, the reference time may bean NTP (Network Time Protocol) timestamp value based on an RTCP of 64bits. The length field of 5 bits may indicate a length of the extensionpayload field. The digital broadcast reception system uses the NTPtimestamp value as a reference time value, such that this reference timevalue can be used as a common wall clock which can be referred at aplayback or decoding time of all the services. Also, this reference timevalue may be interoperable with the other NTP timestamp transmitted assender report (SR) packets of the RTCP on the IP layer.

If the extension field of 3 bits is set to ‘111’, it indicates theextension payload is a meaningless data value. If the extension fieldranges from ‘001’ to ‘110’, the extension payload field can be used as areserved value.

FIC segment data transferring this reference value may be contained inany one of MH subframes contained in the MH signal frame. For theconvenience of description, it is assumed that the FIC segment data iscontained in a fifth MH subframe. For example, a reference time value ofFIC segment data corresponding to the fifth MH subframe is an NTPtimestamp, and the beginning time of the MH signal frame may be set to asetup time of a system clock.

FIG. 28 is a block diagram illustrating a digital broadcasting systemaccording to another embodiment of the present invention.

Referring to FIG. 28, a tuner 410 receives a broadcast signal. Thebroadcast signal may be a signal in which mobile service data and mainservice data are multiplexed.

A demodulator 420 demodulates a reception signal(s). If the receptionsignal is the MH signal frame, the demodulator 420 can output thebeginning time (i.e., MH frame start) of the MH signal frame or thebeginning time of each subframe of the MH signal frame. That is, thedemodulator 420 can output a demodulation time of a specific position ofthe received signal. The demodulator 420 extracts TPC or FIC data fromthe MH signal frame, and outputs the extracted TPC or FIC data, andoutputs the RS frame including ensembles of mobile service data.

An FIC handler 450 can output the NTP timestamp contained in FIC data toa manager 440. The NTP timestamp value may be set to a system clock atan MH frame start time. The manager 440 decodes or displays datacontained in the MH broadcasting signal according to the system clock.For example, the manager 440 recovers the system clock using thereference time, and controls a service table information handler 465, anIP filter 475, a data handler 480, and A/V decoders 490, such that datacontained in the service table information buffer 460 and data containedin the IP datagram buffer 470 can be processed at a constant bitrate.

A channel manger 447 of the manager 440 constructs a channel map on thebasis of FIC data, such that it outputs and displays specificinformation indicating which one of ensembles includes a correspondingvirtual channel according to the binding information indicating arelationship between the ensemble and the virtual channel.

An RS frame decoder 430 decodes an RS frame, such that it outputsservice table information and service data used as content data. The IPdatagram may be contained in an MH transport packet (MH TP) contained inthe RS frame.

Although the example of FIG. 1 includes both service table informationand service data in the IP datagram, the MH transport packet (MH TP)includes section-format service table information and includes theservice data in the IP datagram as shown in FIG. 1.

In this example, the RS frame decoder 430 outputs the service tableinformation to the service table information buffer 460, and outputs theservice data acting as content data to the IP datagram buffer 470. Theservice table information handler 465 decodes the service tableinformation, and stores the decoded service table information in theservice table information database (DB) 480. The IP filter 475 mayfilter the IP datagram including desired service data and may output thefiltered result.

The data handler 480 processes data broadcasting download data containedin the IP datagram. A middleware engine 485 can transmit the data to adata broadcasting application using the output data of the data handler480. For example, the above-mentioned application is outputted to a userby an OSD via the A/V post-processor 495.

The A/V decoder 490 decodes audio/video (A/V) data contained in theservice data in the IP datagram, and outputs the decoded A/V data. TheA/V decoder 490 is able to decode A/V data according to the system clockrecovered by the above reference time.

An interface unit 445 receives control signals for managing andestablishing the digital broadcasting system from the user, for example,a channel change signal and an application driving signal.

The A/V post-processor 495 receives A/V data from the A/V decoder 490,displays the A/V data, and outputs the A/V data according to a controlsignal received from the interface unit 445.

The A/V data generated from the A/V post-processor 495 is transferred tothe user via the display (not shown). The display can provide the userwith the A/V data according to the system clock recovered by thereference time. The manager 440 controls the A/V postprocessor 495 tosynchronize A/V data according to the NTP timestamp established at aspecific position of a reception signal frame, and the display outputsthe synchronized A/V data to the user.

Although the embodiment of FIG. 28 is similar to that of FIG. 1, theembodiment of FIG. 1 can process the signal in which the IP datagram inan MH TP (Transport Packet) includes service table information (SI) andcontent data in the IP datagram. This embodiment can process the signalin which the MH TP directly includes section-formatted service tableinformation (SI). Therefore, as shown in FIG. 1, the reference timeacting as the NTP timestamp value contained in FIC data can be operatedby a system clock at a specific time of the MH signal frame.

If the service table information or the content data is transferred tothe MPEG-2 TS contained in the MH TP, the above-mentioned NTP timestampand other information indicating a relationship between the MPEG-2 TSand the NTP timestamp are needed.

A program map table (PMT) of the MPEG-2 TS is transferred to becorrespondence with each program (corresponding to the service of theabove-mentioned embodiment). The PMT includes information forconstructing a program, and a PID (PCR_PID) transferring a PCR whichrecovers a system time clock referred by an elementary stream of theprogram.

FIG. 29 shows the relationship between the NTP timestamp and the PCR ina PMT according to the present invention. In this case, this descriptoris denoted by an NTP_PCR descriptor.

A descriptor_tag field and a descriptor_length field indicate adescriptor identifier and a descriptor length, respectively. AnNTP_timestamp field indicates the above-mentioned reference time, and aPCR_base field is an STC of the MPEG-2 TS. If an NTP_PCR descriptor iscontained in the PMT, a relationship between the NTP timestamp and anSTC of the program transferred to the MPEG-2 TS can be obtained. Theabove-mentioned NTP_PCR descriptor can describe a PCR of the MPEG-2 TScorresponding to the NTP timestamp.

FIGS. 30 and 31 are other examples of an FIC segment according to thepresent invention.

The FIC segment field of FIG. 30 will hereinafter be described indetail.

An FIC_type field indicates a type of the FIC segment.

An FIC_segment_number field of 3 bits indicates a serial number of FICsegments.

An FIC_Last_segment_Number field of 3 bits indicates a number of thelast one of the FIC segments.

An FIC_update_Notifier field of 4 bits may indicate an update time ofFIC data. For example, if the FIC_update_Notifier field is set to‘0000’, this means that FIC data is not updated but it is updated afterthe lapse of the MH signal frame having the same value as that of acorresponding field.

An ESG_version field of 4 bits indicates version information of serviceguide information transferred to the ensemble to which the service guideinformation is exclusively transferred.

Information contained in the FIC segment payload is as follows.

The FIC segment payload includes at least one of the FIC_Ensemble_Headerfield and the FIC_Ensemble_Payload field.

The FIC_Ensemble_Header field includes an Ensemble_id field, anRS_Frame_Continuity_Counter field, a signaling_version field, and aNumchannels field.

The Ensemble_id field of 8 bits indicates an ensemble identifier. TheRS_Frame_Continuity_Counter field of 4 bits indicates whether the RSframe transferring this ensemble is continued. The signaling_versionfield of 4 bits indicates version information of the signalinginformation of the ensemble included in the RS frame. For example, theservice in the ensemble may be described by the SMT (service map table),and version information of this SMT (service map table) may beestablished in the signaling_version field. In addition, if ensemblewhich is transferred in units of a section is described by othersignaling information, the version information of the signalinginformation can be established by this field. For the convenience ofdescription, it is assumed that the service table information istransferred in the ensemble according to a section format used as apredetermined transmission unit and describes mobile service datacontained in the ensemble.

The NumChannels field of 8 bits indicates the number of virtual channelscontained in each ensemble.

The FIC_Ensemble_Payload field includes a Channel_type field, aCA_indicator field, a Primary_Service_Indicator field, amajor_channel_num field, and a minor_channel_num field.

The Channel_type field of 6 bits indicates a type of a servicetransferred to a corresponding virtual channel. Exemplary values of thisfield value will hereinafter be described.

The CA_indicator field of one bit has conditional access informationindicating whether or not a corresponding virtual channel is anaccess-restricted channel. For example, if the CA_indicator field is setto ‘1’, an access to a corresponding virtual channel may be restricted.

The Primary_Service_Indicator field of one bit indicates whether or nota corresponding virtual channel service is a primary service.

The major_channel_num field of 8 bits indicates a major number of acorresponding virtual channel, and the minor_channel_num field of 8 bitsindicates a minor number of the corresponding virtual channel.

A plurality of fields from the Channel_type field to theminor_channel_num field may be repeated in the FIC payload according tothe number of channels.

FIG. 31 shows another example of the FIC segment.

Referring to FIG. 31, an FIC_type field of 2 bits indicates a type ofthe FIC segment.

A NumChannels field of 6 bits indicates the number of virtual channelstransferred to the ensemble to which a corresponding FIC is transmitted.

An FIC_segment_Number field of 8 bits indicates a number of acorresponding segment selected among several segments created bydivision of FIC body data.

An FIC_Last_Segment_Number field of 8 bits indicates a number of thelast FIC segment contained in corresponding FIC body data.

The FIC segment payload may include an FIC_channel_header field and anFIC_channel_payload field. The FIC_channel_header field may include anESG_requirement_flag field, a num_streams field, an IP_address_flagfield, and a Target_IP_address field.

The ESG_requirement_flag field of one bit indicates whether serviceguide information is needed for a user who desires to view data of acorresponding virtual channel. For example, if this ESG_requirement_flagfield has the value of 1, this means that the service guide informationis needed for the user who desires to view the virtual channel data,such that the user can select a desired virtual channel by referring tothe service guide information.

The num_streams field of 6 bits indicates the number of video data,audio data, and datastreams transferred to a corresponding virtualchannel.

The IP_address_flag field of one bit indicates an IP address providingthe corresponding virtual channel can be represented by an IP version 4(IPv4) or an IP version 6 (IPv6). An address of the IP version 4 (IPv4)may correspond to 32 bits, or the address of the IP version 6 (IPv6) maycorrespond to 48 bits. The Target_IP_address field indicates an IPaddress capable of receiving the corresponding virtual channel.

The FIC_channel_payload field may include a stream_type field, atarget_port_number field, and an ISO_(—)639_language_code field.

The stream_type field of 8 bits indicates a type of a stream transferredto the corresponding virtual channel. The target_port_number field of 8bits indicates a number of a transport port capable of acquiring acorresponding stream. If the stream is an audio stream, theISO_(—)639_language_code field denoted by 8*3 bits indicates a languageof this audio.

FIG. 32 is a flow chart illustrating a data processing method accordingto the present invention.

Referring to FIG. 32, a digital broadcasting reception system receives asignal in which main service data and mobile service data aremultiplexed at step S801. As an example of the multiplexed resultantsignal, the MH broadcasting signal can be used as an example of themultiplexed resultant signal. The mobile service data may bediscontinuously received with time.

The system demodulates the received broadcast signal, obtainsfast-information-channel signaling information in which reference timeinformation to be used as a system clock is established. Also, thesystem obtains reference time information of a specific position of thebroadcast signal frame at step S803. For example, demodulation timeinformation of a specific position of the frame may be the beginningtime of the MH signal frame or the beginning time of each subframe ofthe MH signal frame.

The system obtains a reference time by decoding fast-information-channelsignaling information, and sets the obtained reference time to a systemclock at the demodulation time at step S805. Thefast-information-channel signaling information is contained in aspecific period of the signal frame. In this specific period, data isencoded by content data and another error correction coding scheme. Thedata of this specific period is decoded prior to the decoding of eitherthe content data or the service table information describing thiscontent data.

The system decodes the mobile service data according to the establishedsystem clock at step S807.

Therefore, the received broadcasting signal may be decoded or displayedaccording to a reference time established at a specific time. As aresult, although mobile service data is discontinuously received in thedigital broadcasting reception system, the received mobile service datacan be processed at a constant bitrate.

As apparent from the above description, the digital broadcasting systemand the data processing method according to the present invention havestrong resistance to any errors encountered when mobile service data istransmitted over a channel, and can be easily compatible with theconventional receiver. The digital broadcasting system and the dataprocessing method according to the present invention can normallyreceive mobile service data without any errors over a poor channel whichhas lots of ghosts and noises. The digital broadcasting system and thedata processing method according to the present invention insert knowndata at a specific location of a data zone, and perform signaltransmission, thereby increasing the reception (Rx) performance under ahigh-variation channel environment. Specifically, the digitalbroadcasting system and the data processing method according to thepresent invention can be more effectively used for mobile phones ormobile receivers, channel conditions of which are excessively changedand have weak resistances to noise.

Also, the digital broadcasting system and the data processing methodaccording to the present invention can process service data, which isdiscontinuously received with time, at a constant bitrate.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A data processing method comprising: receiving a broadcast signal in which main service data and mobile service data are multiplexed; demodulating the broadcast signal to acquire fast-information-channel signaling information including reference time information for a system clock, and outputting demodulation time information of a specific position of a frame of the broadcast signal; decoding the fast-information-channel signaling information, and establishing the reference time information as the system clock at a demodulation time according to on the outputted demodulation time information; and decoding the mobile service data according to the system clock.
 2. The method according to claim 1, wherein the reference time information is a Network Time Protocol (NTP) timestamp.
 3. The method according to claim 1, wherein the mobile service data is contained in data groups in the broadcast signal, where the data groups are time-discontinuously received.
 4. The method according to claim 1, further comprising: displaying content data contained in the mobile service data using the system clock according to the reference time information.
 5. A digital broadcasting system comprising: a receiver configured to receive a broadcast signal in which main service data and mobile service data are multiplexed; a demodulator configured to demodulate the broadcast signal to acquire fast-information-channel signaling information including reference time information for a system clock, and output demodulation time information of a specific position of a frame of the broadcast signal; a manager configured to establish the reference time information as the system clock at a demodulation time according to on the demodulation time information using the fast-information-channel signaling information, and; a decoder configured to decode the mobile service data according to the system clock; and a display configured to display content data contained in the decoded mobile service data.
 6. The digital broadcasting system according to claim 5, wherein the reference time information is a Network Time Protocol (NTP) timestamp.
 7. The digital broadcasting system according to claim 5, wherein the receiver is configured to receive the mobile service data contained in data groups of the broadcast signal, where the data group is time-discontinuously received.
 8. The digital broadcasting system according to claim 5, wherein the display displays content data contained in the mobile service data using the system clock according to the reference time information. 